FesslerNoTimeToEatQRB

FesslerNoTimeToEatQRB - \-b1.L'Mr. 73, Ni}. I Mn RCH 2003...

Info iconThis preview shows pages 1–19. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 12
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 14
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 16
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 18
Background image of page 19
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: \-b1.L'Mr. 73, Ni}. I Mn RCH 2003 THE QUARTERLY REVIEW of BIOLOGY N0 TIME. TO FAT: AN ADAPTATIONIST ACCOUNT OF PER] 0V LILATORY BEHAVWORAL CHANGES I‘M rx m. M. T. FESSLER Depa'n'mrrm' rgfxi'ritfrmfmi'agy. Univ-main}: of (Iriiffnfiiia 0.: Ln: Angwa 1’ .0? fl. Hg?! .5; Cufifirmia 90095—1’553 USA I".-M.-‘\ | I .2 DFlub'E'ilj'lREF-‘ANJ HELLULJLA. LIJL' IcI-z‘rwmms nicnsrrual cyclr. pcriuvulalury belum‘iur. caloric inmkE. phyh'it'iil iilfti'riljr'. psychological chnngt‘s AUSTRAI'L'I' :i rmliltJWJieusitJr J'flrlim' a} :mmrn is (Itfl‘aijl mnanim‘ m’TtJfi'h' Her rm‘nsinun'. rfvrir .i'H-flflflh a. (My: in. r-mimir- Imam: “mum! Hm {him a} tfllldflg‘lfl'flf sr-mn’m jireiir'r'mr m't'm m mmr-r' “Hm mri-rmrmi-L The jJHimmi'm‘rJr} nmtn‘ is fmufmg, m if 25 no! expirr'alrir' m ir'rms' rifrfmwgm in Hm mmgy budget. Existing rxpimmfimu in NI? rim'mfli fl'frmfir-rr afilrrrrm :irfrrlih' H! Hm pmximm'r! {rm-i igf'nsuri-{wi'i and 1mm! if“ :m.‘ (Mam-5.5 (Mr {mafia In Hm {min-1'; I nib-r17 rm win-"mir- Haida-runner”fin the furrirmumnrr} fending find”; (grin-rig Hm.“ Hur :inr‘rr'umr in Hue wt jmi'njfin .urtiufl'rm aiming HIP fertiie period {JIM ffflmh’ .rydr ix rm. rirhrfrmflmr frrmi'mwri In: amt-um! Wafertiimr in (MW in radar? Eh? motilraiionai milling"! riff- grunts Hm! :manrr with than? (Hawaii or indircr-rijv pmmininfi m mating. In support Of'x‘hl's expidflflfifl'fl, I add-rm rmidr’ru‘r' 1-5:": a) fan-intruiaimjl mimetic“ in nthm‘ inmtrivr beham'on, and {I} perm;me hirrmm in. mater rr-iiiivilr (mil Hm psrr'haiogitrrii rsrmr'umirrmLs Him]. C("JNSIDERAHIE. ATTENTION has been dedicated to the study at r'hanges in human dietary behavior mm tho;- ruurse of the menstrual ryt‘lté. The vast nuijm‘ity (if this research has lthLst-rl llpt'm late- hlleal phase increases in flmsnmlninn. Wirh a few nnrahle exceptions {c.g.. Lyons at a]. [989; Dye and Blundeii IHQT), ilwmtigarm'fi i‘li-1\.-'t‘ (indicated iith- (11' nu ultenliull LU an equally striking if sonar-what mm‘e muted pattern. the reduc- liun in food consumption than occurs around Ti‘lt“. rime nf nvulatinn. This paper explores patterned changes. in eating and nther behav— iors during the periovulatory period. I begin by presenting data. gleaned from published murms. that demonstratt: the existence of a perim’ulatm'y feeding nadir. I then show that the nadir is nor. explicahle in terms of ener- getit homeostasis. nor can it be explained in terms of the influence of other activiLitts nu 'i'in' an'n’rfi' Rminu rgf'Bminm. March 2mm. VII]. 78. Nu. I (inpyrighl it" 21103 by The University at Chicago. All rights rrscrvcd. 0033-5770! 2003/TSUI-[Hliilfiiffiflil -1 'l 3‘ IF Qt.-fl1R?i‘€FU.Y RE 11TH W OF BIOLOGY feeding, and is not liker to he an accidental lav-product of hormonal changes at ovulatiot't. Reviewsng Evidence of patterned changes in motor activity and related psychological states. I argue that tlte pt't'itit-‘ttlatt'it‘}-' feeding nadir is best viewed as the product of an adaptive mechanism that reduces motivational coulliets between those behaviors that subserve budin maintenance and those that suhserve mating. In short. natural selection has taken account of the fact that, during Lhe fertile period. females have better things to do than eat. EVIDENCE 0}" THE PER]0\-’UI.ATORY NP.an Using the PubMecl. Biosis. Psychlnfo. Worldt'lat. and Melwl electronic databases. and lollowiug a snowball citation strategy, I searched for studies that contain caloric intake data recorded during at least three points in the menstrual cycle, including the period at or near ovulation. This search produced nine- teen publications. sixteen ot' which present comparable quantitative results. Because these sixteen investigations were conducted in pur— suit of diverse research goals. they vary consid— erably with regard to the parsing of the men- strual cycle. .tnakint,r meta-analysis impossible. Data gleaned from these studies are therefore presented in gmphic form for inspection in Figure 1: methods. durations, anti subject pro- files For each studv are described in Table 1. To enhance comparability. in those cases where investigators examined both a special population (e.g.. sufferers of premenstrual dysphoria. smokers) and a control group. only data from the controls were included. Although the effect varies in magnitude, ten of the sixteen studies in Figure 1 {l—(i. 8— llJ, 15) present considerable evidence of a drop in caloric intake at or near ovulation. Two studies (12’ and 14} reveal a much smaller decline at ovulation. One study (13) shows no difference betwt-ren the late. follicu- lar. ovulatory. and late luteal periods: another stud}; (in) shows a similar pattern but with ovulatorv in take being slightly lower than pre- and postovulatory: and two studies {7 and 11) indicate a slight peak at. o‘L-‘ulation. Hence. ten studies support the existence of a periovula— torv nadir. two supva weaker confirmation. and tour provide contrary,r evidence. Note that \-’or .usu-L F8 while the sixteen studies vary, with regard to the rigor of the methods used (see ‘l'ahle 1]. this variation does not correspond with confir— mation or disconl'irmation of the existence of a periovulatorv nadir. making it unliker that the favorable distribution of results is a con- sequence of a preponderance ofweak studies in the literature. In addition to the Work summarized in Fig- ure 1, three addititmal studies report results that are relevant but not directlyP comparable. Examining nutrient intake across the cycle. Abraham et al. {l‘JE-l l) asked 25 Australians to keep daily food logs and menses records. Describng cvclie variation in protein intake as representative of their Findings for all nutrients examined. the authors present results that reveal a clear periovulatorv nadir. Bauml “989) collec1ed food logs and daily weight measurements from 8 Germans. Apparent random variation in intake led the author to suspect that subjects had failed to keep accurate dietarv records. Biiutnl there- fore. used body weight fluctuations as an index ol'chauges in timd intake. as cvciic vari— ation in weight and intake are significantly correlated (Pelkman el al. 2001). The result indicates an intake nadir four days before ovulation. Lastly, Alherri-Fidanza et al. ([998) asked 8 Italians to keep dietarv logs. and used scheduled blood tests to assess hor- mone levels. Although a comprehensive :tccrntnt of findings is not presented, the authors note, "The greatest ditl'ereuce in ener-‘tagjtr intake. kcal 1232 (M_] 0.51) — 8%. was observed between the [I and III Groups of days (respectiver tith. 7th and 8th and 13th. 14th and 15th} predominantly due to the lower consumption of bread at 13th-15th" (1998:1312). This statement strongly implies that the authors recorded a periovulatorv nadir. In sum. of the sixteen studies that contain crunparable quantitative results. twelve indi- cate a pet'icn-"ulatorv drop in food intake. and of the three studies containing less well-quan- tified results, all suggest the same pattern. is l'Hl-I Pr.HltWt|l.n'l'I_lR‘t' NADIR SIGNII-‘lCAN'l‘? Overall, the results presented above suggest that human [bod consumptirm is reduced htlfitltfi H sous around the time of ovulation. Nt-‘verthelcss. given the frequently smail magnitude of the effect. skeptics might question the signifi- cance of this phenomenon—after alll minor perturbations of behavior. however pan terned. hardly call For extensive. investigation. It is therefore important to note that research to date almost certainly underestimates the extent to which humans are prone to reduce [bod consumption around m'ulatimi. All of the above studies were crmducted in modern Western nations. societies characterized by a superabundance and an enormous variety of' food. One consequence of the ready avail- ability of huge quantities of" food is that pat- terns of consumption are profoundly influ- enced by a wide variety of factors unrelated to immediate bodily needs. including per— sonal habits. cultural norms and beliefs. and standardized portions of purchased foods (cf. Hernstein et al. IQHI; de. Castro l'EiFil; Wan- sink 1990: de (lastro el al. 1907: Rolls el a]. 20m): McConahy et al. Eiitih': ‘roung and Nes do 2002). Similarly. because dietary variety increases meal size (Rolls et al. 19811). the CU!" nncopia available to the Western diner likely affects intake. As demonstrated by the fact that obesity looms as a leading public health problem in the West (a circumstance unprecedented in human history}. these Fac— tors conspire to dampen the influence of endogenous elements on human feeding behavior (cf. Young and Nestle 2002}. Seen in this light. the fact that W‘stern women exhibit any periovulatory nadir at all incli— catcs that the phenomenon is probably quite robust. If. in contrast to the contemporary Western case. food is both relatively hard to come by and of limited variety. individuals are unlikely to eat when they are not hungry. suggesting that the periovulatory nadir will be significantly more pronounced among women living under conditions more. similar to our species' environment of evolutionary adaptedness. TH r. Percale or TH}: l'eaiovUtA'l‘oRr Name The. periovulatory nadir is puzzling. To appreciate why. consider another marked fea- ture of caloric intake across the menstrual .4 i' M. i "f 'ei 'i '.i ( LIN A ND I’ERlOi-TA'IA TOR }" Biff-Ll “’0er L If I! irlNGE 5 cycle: a wide variety of studies report a luteal phase peak in consumption (reviewed in Bul- tenstein et ai. 1995; Dye and lilundell IFiFJ’F: see also Danker—Hopfc et al. 1995: Alberti- Fidanaa et al. 1998: Li et al. 1999: Paolisso et al. “399: Allen et a]. 2000: Pclkrnan et al. 2001; but see also (lliappell and Hackney 199?]. a pattern that is evident in many of the studies summarized in Figure 1. Increased luteal phase caloric intake may he compensatory in nature. as the basal metabolic rate increases in the luteal phase {Webb 1986: Ferraro etal. I992: l'Lek el al. I997; Allen et al. 2000; but see also Paolisso ct al. 1999). plausibly due to the energetic costs of constructing and maintain-~ ing the. endometrium {Strassmann IQQfii. Alternate-1y. luteal phase increases in intake may constitute anticipatory preparation for the demands of a possibly ensuing pregnancy (cl. Drewett 1973). In contrast to these multi- ple {and nonmutnally exclusive) explanations. energetic homeostasis cannot explain the peri- ovulatory drop in food intake. Il'. across the entire cycle, caloric intake was significantly determined by the metabolic demands of the endometrium. then. given that the prelimi- nary rebuilding of the endometrium begins in the early follicular phase. we would expect a gradual increase in calorie intake From the early Follicular through the luteal phase. rather than a sudden clip around ovulatirm. Similarly. the heighttmed probability oi" con- ception around the time ol'ovulatiou suggests that. if the prospect of the upcoming increased caloric demands of pregnancy affects intake. there should be a gradual increase in consumption from the late follic- ular through the luteal phase. rather than a dip in the. middle thereoi‘. lastly. because caloric intake in general reflects daily gross energy expenditure. patterned changes in intake might reflect patterned changes in expenditure. Animal models suggest. how- ever, that rather than a drop in expenditure around ovulation. there is an increase that results in a net energy deficit {Wade 19276}. As will be discussed at length. the periovu— latory period is marked by an increase in motoric activity, hence a simple match between expenditure and in take cannot explain the periovulatory nadir in Food con- sumption. 6 THE QLMRTERLY HE l-"HEW 01'" EN H .(Jl’ :‘l’ V1311] ME 73 Mann}: 1_ [ermzhh |_\ LJ_-u,uh:|t_ lNI'r\!\'l-_i1l.L.Rl.)'§5 'I'1Il-'_ S-lI-ZNS'I'IHIM.{LYLLF Dam 1151' the ovuliuury LII' ]_u-_-:'i|,w||l:.|||"'3' 1w: iulrl .ll't‘ .slmwn in hlLLEk. (:lhu'L l slmwa t'CS-lrlllall rllt‘l'gj.’ lll’ullu: in KC::III,"l—Jillt"l nll mlleu ('Iharm shnw mum inlulu- in KCaly’DaLjr. Mlch = middlc Gl'lulllculal' phase: I‘.) = UVlllEItlL'III: F} + # = uumln‘r ul‘dafis} pmlm’nlminn: Mitll. = mid-Eln- ()I'ILm-ul plluuu: Perl.“ = perinwrmrnul Elwin-ll; M = Int-1mm: I" = follicular phase; l’criU = Pt‘l'itu-Lllillul'y [ml'ilul: [. Inn-:il plum-L PI'JHI() = pulimwlalt'n'v |)Cf'l0d‘.l"1’L'M = prennrnsu-unl Emiml; Early I. - rm'ly lulval plumc: LIL-L- L = lellt‘lllLCfll|}l1115(':5’lld‘l. = mitldlr luteul plume; lull.- F lall- fi'allirulm' plum: Mid-F = Illicltllc [bllivular pl'i:1.~;c: I‘Zm'lv [" = #321113.’ llallintulm' phase: Pre-U‘ = {JI'L'ut-ulalnr'f.‘ lav-rind: Pnsr—O = pnsmvulalory period. n— M A mm 2003 ADAPTA '1' DION AND PEIHUVUM T UHF HEI- M WORM. CHANGE r' THE QELILRTERLI" HE WEI-1" OF BIOLOGY Chart 1 L“ -.J (I Subjects TABLE 1 30mm: qf data prawn-cl in Fignrc l Methods Duration ‘23 Nnrth Americans. ilgr ‘32—“. I'll-ullll'y, tlllllelll!Lll1H.llL'J ural {'llntnll'elltivfl [HI-i) IL-ila I'tt‘l WVI‘H‘ prmncnsunal syndrome “I North Amcrlcams. age: 24—43. llcaithy by medical history and labs. not abuts-u. no current UK. medication, In flirting; rle length Eli—3F: rings 13 Australians. agr- |7-- Fifi lmrnn Elf-Hi), Inlllnnl wright. mil Hiking (ii—i [I'll at Itaat 2 months. licalthy. not dieting. no psychiatric or eating disorders: Cycle of 23—34 days for past h months {I NIthI'I r'inll‘lil'ilnn, Ill’ll'lHTl'lfllelg, lllll'llnll wriglll. :lgl-I 1331—33-5, llihlll-I')" lJl' iii-Hula] nit-l'lstl'ual cycles. I'ID (lit-ting. ()(T. or ltgnlar medication for I year prior. full physical examination. pal‘miitc check El?"- Nnrth .r‘unln'ittnns. llnrnnll wright. nu eating dimmers. anc- 22—139. rcgula: menses during past 6 months. no mbaccu. 0C, or medication LIB-C. not pregnant It'- Licrn'lanl.11gc til—rlfl. l't'gtllill'l? l'lll‘lll'lll'llillillfl. In: (M: 1M [5 North Americans. age Ill-:55. nnliiparoua. nu tnhatcn 01' 0C inc. 1m dieting or eating disorders: cyclic 26-30 days. BM] iii—25 kg! m2 [6 Italians, lcan. HUI. pregnant, ltlrtnliilg, liillllnliti. Ilr giucum‘. Jllttlirlulll. [ice llr illness. lltll using lobar-:0. or drugs. nut dicting, suhk: body wright for pun-int“ 5 months: cycll' length Elli—Lit} days it N'th Amrrirans, [nl'i-ITI agr- EHB. regular (Till-.5 Eli—H lint-'5. normal wcight-iiJr-htrigh I. nn substantial Wighl fluctuations in prcvious 6 months. no dieting. 0C. or medications: l1t.'l l'Hl'l-Iu nlremlill HVFI'ilh Lab wrighing nfall find and uncatcn pol-110115: fiElfPI'BIMJI‘ECIl. onset of I'I'ICllfiittii. standardized tn 23 day cycle Tupc-rccnrdcd [‘L‘L'tn'd of diet and activirj", Hind-l weiglwli [Il'llfl' In Filling. lilnll'. wax”: wrlgllrli ill-It”. daily UI'C‘LI l.l‘.l1l|.ll:lul.Ll.rt' Stilllvciglnng {if all lands and liquids. daily log: daily lll'llfll‘ mtlnction with lab analysis of LH levels ('iunfllllfll tn t'ttt'rtill'Lll Ill‘tit. fixed and unchanging amount (if physical activi I}; per day; all tho-cl and liquids provided by Htafi': unbuknuwnsl tn whim-ts. precise amount ilnt'il conic-ms; rif' all funds nnri liquids E'Ulliilllflt-‘l'i til-It-nnilmll :Iilvr I‘llt'll rlwlll III muck ln' slilll; “I'll-i“! il-‘I Illlillh'tfh i'l‘I'III'llllll Hull-rhuuldull fund ullllltL' using supplifll forms: daily temperature upon awakening: sclf-rcrcurzlctl trxcrl‘lfir: type and duration: weekly lab visits wiLh himxl analysis for |.HI l-‘HH. prngl'srrmnt', curildinl Ilnill.I wriglwli lull-ll HPlf-l't'pl‘lt'l um] lilth'id Itllllfflfl'illltl'l' Dailyr fund intakc rem-rd. (Nulatiun prediction [til (lulcinizing hormone llctcctnrl Daily weigh cd limd rc m rd plus (<:ull1p;lluliw) ruli'tnlp-ln'.ti\r't- q u esLiun :1 iii t'c'. daily rec tal temperature Ilnii}I iilnll rt-t‘nrrl, iln‘inclingr wmgltlllg im' IIIJIIHmlltIilI'llifl’tl items; clain oral lcrnprralurc At least UTIL‘ I'LIII Eyck: {two studies, durations n: 4‘}! and Fifi (law) 0an full cycle 35 clays 52 flats Dill: Unit: A! lHuM U'I'It“ l‘ll” l't’l'le 0m: t‘ult cyclc Onc i'nll cycle {inc Full cycle lemr TR Reference Lissm-r cl al. “335-! tiling l‘.| till lill'iii Lyons ct al. 1989 Foug and Krclach lFJ'S‘fi _|ulnlsnn Cl ill. 199-1 l‘inllkH' HllleH H i-Il. HIE-if: Eck rt 3.]. 199? Paniism er a]. limit Siophos Till-iii MARIJH 2003 10 ll Hi 1:") North Americans. age lH—Hfi [mean = ‘26}, regular t't't'it- Ill Ell—.555 tlztrh'. ttu ut‘u] L‘lf iltlplal‘tl tztmltmeplivc use. no dieting. mnultjrtg. gynecological problems. or regular medication use; nnl pregnant within last year. not nursing 15 ['40th .Mnericans. age Ill-35 {mean = 19.9],goodhcaltl1. regular cycle of Elli—fill rlttys, HMI Ill-$25 kgfmli, rlttlli[l:.n'ultrt1 1m fitting tlirittltltu's. medicaLluns. winking. I'JJ' gynecological [nuhlrunt l':l Hutu: Amt] iLana. mean fig? 2?.?. not taking 0C for at least 2 months. not pregnant or lactating. rt-t: psychiatric illness. dieting, or gynecological problems; regular menstrual cvclcs lest: than 35 claw. THJrTHfll BM] Ill Nnrlh Amfir'tt‘nrm, ngt‘ Hi 45- (tlttetm — 33.2].110 ttlcdltal Ul psychiaLric illness. regular crclcs ul‘ 25—31 days. no hormuna] or psychoactive medications for two months prior. normal BM]. no eating disorders or significant ncgativc rmmd differences across cycle Il—l \tirlh ATIIFrlI'HIIH. agr- Il'lw-‘lfi (Int-jut — 217}, healthy, I'LH medical 0] psychiatric Pl't'l-l'lllill'lft. 1m mcd'tcaL'tun-s c-I fill—lr nut pregnant timing pnwiutL-t .‘l IIIUIIIJIN. Itgulm cycles tawmgc = 23.? days}. normal BMI 5 North Americans, age ill—25 trncan - 21!};cyclc'icngth 2‘}— ‘lfi (mean = Lilli}. healthy, tltntlmtl all'ulml ittlilltti. I1” silmlting nr' ( HI Ii? .Ntn'll] Aluminum. mm." age = 24.4; cycle length 28—30 days (mean =29.?}. no recent stresses. medicallnns. or DC. modest cafl'eine intake, not [l'l‘figtl'dflll ntlrmttl HM] Ilttilv lllllll lug: wilJt Ittticlum tult'plluuc Lnuniml'ing l'ul' accuracy; oral temperature. home mulaliorl prediction ltit Ont: practice cycle, nnc' study cycle; Ilnilj' l'tmtl rerurtlyir lmtlltr lmtlttlitm lll'ctllL‘lll'lll kit Urn: practice cyclic. one test cycle: daily food record-JI- folluwing training using modem; tiara {'fillt'f'lt'l'l fnr l'nur [lfillfifi'fi per plume: mth Ill llll‘llfil'fi It:t:t||tlrtl Ftinll t.li.;1r3-I lullnw‘tng lluiIlillH with models; basal temperature l‘rniltr luml llittriHrt ltlllnwiilg Itainutg thJI Illllllfllfi [III lwt: cunsccuLivc days during each of four phases; onset of menses recorded Daily fmxd diaries. mute: of monies: rccnrded lit-II using once weekly 24-hour food tlittrir and record of current mensmtal alarm and '(‘T'uflfi-firll'lilllliLl design date 01'0th of last memes: rtltl‘tjer'ts unaware nfrenfitrrh le’lgiEt'lth“: Clue l] 111 cycle Um: lull I'yt:l1' One l'ltll cycle 5—9 wt't'lui l'wn I ull I"_§-'l 'lffh' 1—2 cycles Hint weeks ADAPTATION AA!) PEMOVULATORY flEH/l WORA I. CHANGE Dc lion 1 991? Brunt-IL [9'34 Httlten-Vir'dlx‘u I'll” Vlt' L: 1 9‘5"? Nt-Itlltiux Il-lllll Adams I985 Wu II I Ell-l7 9 it] THE QLHHTERLY REVIHM’OF BIOLOGY THE PERI-ESTRUS NADIR IN ANIMALH Human feeding behavior is profoundly determined by cultural constructions of diet. gastronomv. and the meaning of eating (cf. l_Iaplan IQFJ'FJ; Rosin et a]. 1099}. Similarly. cul— tural models iniluencr experience anti behavior across the menstrual cycle (Cl'. Fitz— gerald 1990: Lu 2001]. It is therefore not inconceivable that ideatiuual factors some how shape human feeding behavior around ovulation. Granted. the fact that the same pat— tern appears in samples of North American. Italian. German, and Australian women sug— gests that culture is not a primary determi- nant of the petiovnlatot'v nadir. Because these societies are all related. however. avail- able. results do not allour us to rule out such a possibility. More persuasive. therefore, is the observation that the same pattern occurs in a wide variety of other mammals: a pen-estrus nadir in food intake occurs in chacma baboons {Bielert and linsse IQHR], rhesus macaques (Czaja 1975; Rosenblalt el al. 1980; Mello et al. l985: Kemnitz et 3!. I989), owl monkeys (Rauth-Widtnaun ct 3.}. 199(5), dogs (Houpt et a]. 19739). pigs (Friend “4'73; Rollin er al. 1989}. goats (Forbth IQTI). sheep [Tart— telin 1968‘. Michel] 1979). deer [Wong and Parker 1938), cows (Ratio et al. 1967]. guinea pigs (Czaia and (Joy 1975). and rats ('l'arttelin and Gorski l97l; Drewen 1974; Elan-stein and Wade lgifi: Eckel et a]. 2001.)}. CoMPc'rIstG licnavtoas Do Nor EXPLAIN THE. Name Naturalistic observations oi'common chim- panzees (Matsumoto-Oda and Ode. 1998), citation baboons (Saayman 1970: Bielert and Husse JQRB). tonkean macaques (Aujard ct al. [993). black-tailed deer {Wong and Parker IQBH), and Richardson’s ground squirrels (Michelier and McLean 1996-) all reveal marked changes in fcutalcs’ activity budgets during the peti—estrus period. More time is spent moving from one location to another and. often. less Lime is spent feeding. This raises the possibility that the periovnlatory nadir is :t consequence oi‘ a sudden increase in competing demands on the individuals time. While I will argue that cyclical changes in the immediater relevant limess goals are indeed cenrral to the ultimate explanation VOLUME 78 for tilt: periovulatot'v nadir. multiple lines of evidence indicate that the nadir is not directly caused by the impingement ofother activities on time available For feeding. First. it is highly implausible that time constraints affect caloric intake among Western women. The ready availability of prepared foods makes the time demands associated with feeding remarkany low; note. for example, that two of the studies reporting marked nadi rs employed profession- ally prepared foods (Lissner et a]. 1988: Fong and Kretsch Hit-iii). Second, rodent studies reveal that the estrus drop in food consump- tion occurs independently of changes in act- ivin levels: when tats are provided with an exercise wheel. their lommotion increases markedly at estrus: however. the. depression in food intake occurs whether the wheel is pres ent or not {Eckel et :11. 2mm. PROXIMATE (hoses or THE NADIR awn ‘I'HF. Bv-Pnooncr HY‘PD‘l'l-IESIS Rather than being a result of a time allo~ cation conflict. there is substantial evidence. that the periomtlatory nadir is produced by discrete neuroendocrine mechanisms. Expeo imental manipulations (ot-ariectotuy and/or the use of exogenous hormones) reveal that estrogen and/or estradiol are directly linked to the. periovulatory feeding natlit' in baboons (Bielert and Busse 1983). rhesus macaques (Ganja and Go}! |9?5; Kernnitx. ct a1. 1939). owl monkeys (Rautll-i‘i’idtnann 1989. cited in Ranth-Widmattn High). dogs (Houpt ct al. [979), cows (Muir et a1. 1972]. rats {Wade and Zucker Hm]; Tarttelin and. Gorski 1971: Blaustein and Wade [976). golden hamsters [Morin and Fleming IQ?R), and guinea pigs [Czaja and Gov 19733]. Although the specific pathways may he multiplex [sec Bttfienstcin et a1. 1995; Gearv 1998). a growing corpus of evidence indicates that estmdiol exerts its effect on feeding behavior in part by poten- tiating the activity of cholecystokinin {CCKL a peptide released front the small intestine during meals that is a principal determinant of satiation {see Geary 200i). The petiovula- mry nadir in food intake is thus in part the product of a mechanism that reduces meal size by lowering the satiation lllt'csltold. It is possible that. rather than serving an adaptive purpose. the potentiation of CCK‘s Ma Run 2003 satiating influence is an accidental conse- quence of some feature of estradiol', perhaps inevitable design constraints or issues of path dependence have preserved a by—product effect over time. The by—prodoct explanation is weakened. however, by the observation that ovulation is accompanied by parallel declines in other ingestive behaviors. In rats [Tarttelin and Gorski 197]; Eckel et at. 200th. pigs [Friend iEiTEi; Rollin et a1. 1930), sheep (Tart- teiin 1968: Michell was, cows (Macfarlane I967}, and, apparently. humans (Fong and Hretsch 1993}. water intake exhibits the same cyclic changes as food ittlake. Although food intake and water intake are generally behav- iorally linked {Engell 1983'. Mathis et al. 1996']. the periovnlatory reduction in water intake is not a secondary consequence of the reduction in food intake. but rather reflects changes independent of those responsible for the decrease in feeding. Specifically, there seems to be a periovulatory increase in the osmotic threshold for tllirst (Rollin et al. 198?}; but see also Vi'ikes et ai. 1988}. Estrogen appears to directly modulate tlte effects ofthe dipsogenic peptide angiotensin (jortklaas and Buggy 1984; Kucliartayk 1984]. In ha!— mony with changes in water intake. sodium intake exhibits a similar cyclic nadir in sheep [Michell lilTfi), pigs (Rollin et al. 1939). and rats {Danielsen and Buggy 1980), apparently again due In the interaction of estrogen and angiotensin {Danielsen and Buggy 1980). I lence. estrogen and estradiol lower both the satiation threshold for food and the satiation thresholds for water and salt. Because the patl‘nvays whereby these effects occur are independent of one another. it is unlikely that they are merely accidental hy-pi'oducts: reducini-el one ingestive behavior might be an accident1 but independently simuluuicously reducing a second itigt'stive helia'v'iol' smacks of adaptive design. Moreover. evidence from other facets of ingestive control mechanisms supports the conclusioi't that the timingI of these changes is not accidental. Across mammals. estrogen and estradiol are key proximal determinants of female reproductive behavior {l’faff [Fit-ill). The fact that ho: monies which promote reproductive behavior also dampen ingestive behavior is wholly consistent. with larger patterns in the neurophysiological mechanisms that regulate ADA EVA '1 TUN A NT) PERIOVI LEA TUR l" BEE-i WORA I. f .1! JANE-3E l ] these two forms of activity. For example, in rats, stimulation of the 5-HT1A serotonin receptor inhibits lordosis (L'phouse et all. 1992} and facilitates feeding (I'lnrxon 1990). t'lonversely. blocking activity at the 5—HT2L‘. receptor inhibits lordosis [Wolf et a]. 1999) and hence, presumably, stimulation of the 5- HTQC receptor facilitates lordosis {see also Ahlenins NBS}: stimulation of this receptor also inhibits feeding (Vickers et al. 1999). Stimulation of the fi-HTEC receptor causes oxytocin release (Bagdy 199(5); exogenous osytocirt decreases feeding (Arlctti et al. [989] and increases female sexual receptivity (Benelli et a1. 1994). Finally, blocking the effects of nettropeptidc ‘t’ prolongs receptivity (Clark 1992) , facilitates lordosis, and decreases feeding tMarin-Bivens ct a1. 1998}. The pros- imate mechanisms responsible for compli- mentary changes in ingestivc and sexual behavior thus exhibit Lhe sort of convergent complexity associated not with by—pt‘oducts bUt rather with adaptationswrteatures produced by natural selection in the service of a specific ultimate goal. That goal. I suggest. stems from the fact that time is a limited resource. BEHAVIORAL CZHtttrtais Duanvr; THE FERTILE PERIOD BEHAVIORAL CHANGES IN ANIMALS In all of the nonhuman animals discussed above, iii keeping with the increased possibil- ity of conception, the period around ovula- tion is characterized by a substantial increase in sexual activity, with females becoming both more pt‘oceptive and more receptive toward mature males. In most mammals, females are most likely to conceive if they maximize the amount of time dedicated to mating activities during the fertile window. I propose that the proximate mechanisms described above serve the ultimate function of reducing the conflict benveen foraging activities and repro- ductive activities. Finding food, water, and salt takes time. By lowering the. thresholds for ingestive satiation. the mechanisms described above reduce the quantity of food and water sought, thus reducian| the time dedicated to foraging, thereby freeing up more time for mating activities. Skeptics might object that. for many lIl'dIIl- mals. copulation does not take very long; 12 THE Qt.-HRTERLY REVIEW OF BIOLOGY hence titne constraints would not seem likely to play a role in relative reproductive success. (lopulation is merely the punctuation mark at the end of the matng process, however. For many mammals the most time—consuming incet of mating is not copulation but mate seeking. As noted earlier. naturalistic studies of chimpanzees. baboons. macaques. and squirrels all reveal that. as the fertile period approaches. lit-males move around more. often expanding their typical day ranges: the saute is also true of kangaroo rats [Behrends et al. 1985]. More carefully controlled labo ratory studies indicate. that increased loco- motion is a hallmark of estrus or its approach in rats (Eckel et al. 2000). golden hamsters (Moline and Albers 1988). ferrets {Donovan 1985). cows (Arney et a1. 1994), pigs (Flowers 1997). and owl. monkeys (Rauth~Widmann et al. 199th. Indeed. the increase in locomotion is so marked that it can be used as a reliable index ot'the fertile period for purposes oi'ani— ma] husbandry (Kiddy 1977; Maalje ct a1. 1997). Presumably. peri—estrus increases in movement. function to enhance the likeli- hood of encountering a desirable mate. a goal that has been clearly demonstrated in controlled studies of sheep (Ortman 2000) and deer (Wong and Parker 1988]. Labora- tory experiments indicate that. like a mirror image of the pericstrus decline in feeding, the increases in locomotion are a direct con- sequence of the changing hormonal milieu, as administration of exogenous estrogen or esu-atliol induces locolnotory increases in mice (Garey et a]. 2mm. rats {Wade and Zucker 1970), Syrian hamsters (Widtnaier and (Zampbell 198”). golden hamsters {Tait— ahashi and Menaker 1980). and owl mon- keys (Rauth-‘Nidmann 1989, cited in Rautlt- Widmann [995). BEHAVIORAL CHANGES IN HUMANS [in humans exhibit the sorts of cyclic changes in behavior described above? First. human sexual behavior is remarkably plastic. Nevertheless. although women engage in both proceptive and receptive sexual beliav~ ior across the menstrual cycle. increases in sexual activity, sexual desire, and sexual sat— isfaction are frequently reported to occur around ovulation (Hedricks 199‘1; Regan VOLUME “F8 1996; Clayton et al. 1999}. Second. although results are mixed, there is substantial evi- dence that. like other female mammals. women exhibit spontaneous changes in motor activity around the time of ovulation. The first attempt to systematically esamine changes in motor activity across the men- strual cycle was that of Billings (I934): ti wotnen. age lb to 33, wore pedometers every day for one or two cycles. Reasoning that they were free from the demands of nortnal life, Billings employed psychiatric. inpatients as subjects. Five subjects showed postmenstrual peaks in locomotion [one with an ovulatory nadir), and one subject showed both ovula— tory and postmcnstrual peaks. These results differ from those reported for nonhuman animals, but Billings's study is highly prob- lematic, as subjects suffered from such disor— ders as schizophrenia, depression. “agita— tion.’1 and “stupor.” the vicissitudes of which likely affected locomotory behavior. Morris attd Udry (19’?0J applied pedome- ter measurements to 26 healthy North Amer— icans I: “typical age" = 30}. who had regular cycles and were not using oral contraceptives. Subjects, the maiority of whom participated for three or more complete menstrual cycles, went about their daily lives. Pooling results and plotting them onto a standardised 28 day cycle. consistent with the results from animal studies, Morris and lidry report a significant Inidcycle peak in locomotion: additional peaks occur at the beginning and end of the cycle. “’hile promising, these results cannot be taken as definitive. as the use of a stan- dat’dized cycle. is somewhat problematic [_ see Hedricks 1994). In a third pedometer study. Chrisler and MeCool (1991] used daily oral temperature readings to generate a more accurate divi- sion of each subject‘s cycle. Seven North American undergraduates, participating for six weeks, served as subjects: no information is provided on age. weight. health, men- strual regularity, or oral contraceptive use. No significant differences in activity level were detected between phases. The appar- ently poor subject screening and limited study duraLion main: this result difficult. to interpret. however, particulariv given that the phaseg’activity association approached Mason 2003 statistical significance. Linlortunately. the data cannot be revisited as they have since been destroyed [I] (.illI‘iSlEI'. personal com- munication). Stout: and Klinge {19753} employed an acto- meter worn on the. nonpreferred arm 24 hours a clay. Subjects were '3’ North Americans wlto were physically and psychiatrically nor— mal. age 2] to ill. ttulliparous. had regular menstrual cycles of 27 to Fifi days. and were not taking oral contraceptives or medica- tions. Oral temperature was measured daily. Subjects. participated for between i and 5 complete cycles. fitettn and Klingc report considerable intersubiecl variation. with no overarching patterns across subjects front measurements recorded :34 hours a day. Since ancestral humans were likely sedentary at night in order to avoid predators. however, an evolutionary perspective suggests that pat- terned changes in activity should occur pri- marily during the day. Looking only at day'- timc movements. two subjects show absolute peaksjust prior to the tnidcycle thermal shift. one subject shows a relative peakjust prior to the shift with a second peak in the luteal phase. ottc subject sltows a dramatic absolute peak several clays after the shift. two subjects show gradual increases across tltc whole cycle. and one subjeCt shows a nadir at the shift. Hence. four out of seven subjects show peaks in dayLime arm movement around the time of ovulation. two ottt of seven subjects do not show marked changes. and only’ one subject shows lovi- levels oi‘ activity at ovulation. Investigating changes itt energy expendi- ture across the menstrual cycle. Howe, Rum-- [,iler, and Scale {Milli-i} examined [‘2 North Americans. age ‘21 to 45. of normal body weight. As confirmed by blood hormone assays. during the menstrual. pcriovulatory. and late luteal phases, subiects spent 21 hours in an enclosed calorimeter. Although some activities were scheduled. subjects were also able to move about freely. in contrast to lind— ings in the animal literature. Howe. Rumplcr. and Scale report that. a significantly lower per centage of time was spent in movement dun- int;I the periovulatory phase than during the menstrual and Ittteal phases (the authors do 1101 describe how activity was recorded). IL is unclear how confinement in a calorimeter AUAJ—"t' A 't' ‘t' t’. J .-v xi. NT) PEEK) l’l ILA TOR Y BEE-’1 WORA i. (leiNt l 3 might. affect women‘s spontaneous behavior. however. If women's changing proximate goals largely revolve around simple. motor patterns. then confinement in a caiorirneter should not affect activity. in which case these results contradict. the hypothesis that ovula— tion is accompanied by increases therein. if women‘s proximate goals involve higher- ordcr HI!leCCLi\-'C experiences, however (e.g.. an increase in wander-Inst or a desire to see new faces}. their the calorimeter method may not be ecologically valid for the question at issue. f'ionlinement during the pcriovulatory phase could. for example. lead to dejection and a corresponding decrease in activity. 'While less precise than the. mechanical measurement of movement or the observa- tion of confined subjects. daily logs provide another ttteans ol'exatnining activity over the menstrual cycle. in two ofthe studies of die- tary behavior summarised in Figure ]. inves- tigator s employed daily logs as a means oi‘esti- mating motoric energy expenditure (:3 Factor to be controlled for. from their perspective}. Eck et al. (1997} report a (nonsignii‘icantl snhpeak itt activity related energy expendi- ture at ovulation. with a second peak during menstruation.Johnson et al. H.994} report a marked peak in exercise related energy expenditure at ovulation. This pattern did not. reach significance, however. presumably clue to substantial intersubiect variaLion. In a lengthy and detailed live tnonth study. Altmann. Knowles. and Bull (194]) examined 10 normal weight North Americans. age 22’ to lift, with cycle lengths of 23 to Ft! days. Rectal temperature readings were taken daily, and subjects visited a lab dain ata fixed time. Vag— inal smears were taken for microscopic eval- uation of cycle related histological changes. and the electrical potential was measured between fingertips immersed in salt water {this study predated the use of blood hor— mone. assays to parse the menstrual cycle). Extensive interviews regarding the subiect's current thoughts. feelings, and activities were conducted daily. The authors report protni- nenl peaks in physical activity at or near ovu- lation in 85.3% of recorded cycles and in the late luteal phase in Fl.8% of recorded cycles. lulriguingly‘. the two peaks are qualitatively distinct. as the periovulatory peak is typically 14 "l 'i' If“; Qt .J'fl HTERIJ' REVIEW OF BIOLOGY associated with a positive mood, often with feelings of elation (cf. Henderson and ‘Whis sell 199?: Smith et al. 1998), while the pro- menstrnal peak is associated with tension (cf. chldewicz and Shiovitz 200]}: in a number ofsubjccrs the premenstrual peak in activity strikingly revolves around house-cleaning activities {ch Wang 1923 on cyclic changes in, respectively. running and nest building in the female rat). ECOLOGICAL VALIDITY AND THE NATURE OF MU'I‘lVr‘l'l'll'lNAl. ('JHANGES To summarize the above. results, some investigators find a substantial periovulalory peak in locomotion and related motor activ- ity, others report a less robust pattern. and some fail to find the effect at all. ('Ionsiderable variation in both the methods Llsed to mea- sure activity and the techniques employed to parse the menstrual cycle make it difficult to compare investigations. Perhaps even more significant is that all oithese studies were con- ducted in modern societies. a context that may obscure the effect. at. issue. As Billings correctly pointed out. in 1934, the habits, obli— gations, and routines ol'daily life in a modern society likely confound any changes in activity levels that stem From endogenous processes. Most of us lead very scheduled lives, and this extends boLh to physical activity in general [how much of your daily locomotion is a product of exogenous demands?) and to exercise in particular (aerobics classes. tennis matches). Moreover, as I noted in discussing the Howe, Rumpler, and Scale calorimeter study “993), investigators have employed methods that may not address the question at. issue here. It is possible that women experience a desire to “stretch their legs" at outlation: i.e., a direct impetus for increased locomotion. The tjohnson et a1. finding that exercise increases periovulatorily is consistent with this possibility. as is the finding that women who exercise feel substantially more vigorous at ovulation than do sedentary women, a dif- ference that reverses itself later in the cycle (Mahoney and Smith IQQT; but see also Hack- ney et al. 1991]. Given human psychological complexity, however, it is likely that such highly proximal motives would not be the VOLUME 78 sole Factors selected to drive midcycle changes in behavior: even in infrahnman spe- cies it is clear that locomotion is nol an end in itself, as animals engage in goal directed behavior when given the opportunity to do Hence. rather than experiencing subjec— tive states linked only to motor activity. women may well experience changes such as l‘cabin fever." a desire to get out and see the World, to meet new people, and so on. Evi- dence consistent with this proposal comes from a study ofvoluntccring bchavim' among 117 North American undergraduates {Dory and Silvcrrhorne IllTH]. During class, stu- dents were asked to provide various infor- mation. including menstrual cycle length and date of recent menses. Some days later exper- imenters solicited volunteers [in experi- ments. Social security numbers allowed the investigators to match volunteers with the data collected earlier and thus to calculate volunteers' current menstrual cycle phase. Women in the periouilatory phase were sig- nificantly more likely to volunteer for exper- iments than were women in other phases. sug- gesting that ovulation is indeed accompanied by increasing in lerest in new experiences and/or a desire to meet new people. Note that, in contrast to behavior in the artificial setting created by Doty and Silver— thorne [.IQTEJ), the naturally occurring behav- iors that have been measured to date are such that a modern lifestyle is likely to obscure the influence of any cyclical motivational changes. First, locomotion is a poor index of such changes since, in many Western locales, subjects who wish to visit new areas are more likely to use vehicular transport than they are Lo walk. Second. if higher-order subjecLive changes monvate behavioral changes across the cycle, a modern environment may radi« cally attenuate motor activity because books, television, movies, and the Internet provide virtual experiences that (spurionsly) satisfy desires to temporarily change one-'5 sur— roundings and interact with new people. Seen in this light, given that all studies to date have been conducted in contexts that. diverge drastically from the conditions in which ancestral foraging women acted, it is striking that the evidence of human periovularory behavioral changes is as robust as it is. MtMtt'JI—l 2llllfi In addition to entailing changes in moti- vational patterns. the. claim that human ovu- lation is associated with increased ranging behavior suggests that navigational abilities should also exhibit regular variation across the menstrual cycle. A siaeable corpus of research has documented significant sex dif— ferences in human spatial cognition (reviewed in Harrison 53000: Silverman et al. 2000: see also Saucier et al. 2002). A robust feature of this pattern is greater male reliance on an "internal compass” and greater female reliance on landmarks. Addressing this dimorphism. Silverman and Eals (1992] argue that a sex-based division of labor in ancestral foragcrs selected for complemen— tary spatial abilities. Ilunting, a predomi- nantly male activity, requires the ability to fol— low game for long distances across the landscape, concentrating on the prey while still maintaining knowledge of the distance and direction to base camp. In contrast, gath- ering, a predominantly female activity, requires the ability to recall the locations of fixed resources, move efficiently between them, and return thereafter to base camp. Harrison (2000) tested both young and elderly women using a realistic virtual way-- finding task. In young women. comparing those on their second or third day of men— struation {when estrogen is low) with those two days prior to ovulation (when estrogen is high}, Harrison found that the latter group exhibited a significantly more malelike pat- tern, relying far less on landmarks for navi— gation. Similarly. among postmenopausal women, those receiving hormone replace— ment therapy that con Lained a sizeable estro- gen component were less dependent on landmarks than were women not takit'tg replacement hormones. Harrison concludes that estrogen shifts female spatial reasoning to a more male-like pattern. This suggests that, compared to other phases of the men- strual cycle, during the pcriovulau‘n'y period women are better equipped to travel in a malelike fashion: to. to range farther from home and pursue mobile rather than fixed objectives. This is exactly the. result that we should expect ifnatural selection has shaped the mind so as to enhance mating opportu- nities during the fertile period—whereas ADAPTA WON AND FERN) VL'LA 'l' '(lli’ i’ BEHA l-fl’flz‘b’lL CHdNGE 15 men pursue game, pcritwulatory wot'neu pursue tncn. THE QUESTION or FUNCTIONALITY I have argued that. like other mammals, humans possess psychological mechanisms that would have led ancestral females to spend less time foraging and more time in activities that cart lead to mating. In keeping with Ilte highly altricial nature. of our off- spring, however, extended mating relation— ships are almost certainly the norm for humans (cf. Murdock lilti7; van den Ecrghe HRH}. This raises the question of the need for such mechanisms: if. over the course of our species' history, a woman's mate has gen~ orally been readily at hand, why would natural selection maintain complex psychological mechanisms that presumably evolved in soli— tary mammals for the purpose of increasing the likelihood of encounteringa mate during the fertile period? To begin with, note that many of the animals discussed earlier live in sizable social groups containing litany adult males. In such species an indiscriminate female interested only in finding a willing mate would not need to substantially decrease her foraging and increase her movements, and this is particularly true if] the many spev cies possessing advertised estrus. The fact that marked behavioral changes nevertheless occur in these animals therefore suggests that the psychological mechanisms which initially served simply to facilitate contact with males have been exapted in social species and put to a related purpose: decreased female for— aging and increased female movements dur- ing or just before the fertile window likely facilitate "shopping" for alternatives to those current or potential mates who are readily at hand. Numerous potential benefits of such female choice have been proposed including good genes. offspring heterogeneity, infanti— cide prevention, attd increased male invest- ment {reviewed in Small 1993; Barash and Lipton 200]}. In theory. "shopping" for alternative mates can provide fitness benefits to women that are similar to those thought to underlie nonhu- man female extra—pair copulations {reviewed in Greiling and Russ 2000). Consistent with this perspective. periovulalot‘y changes in Iti THE QIMRTERLY REVIEW OF BIOLOGY women‘s olfactory (tiangestad and 'l‘hornhil] 1998) and visual {Frost 1994; Pellton-Voalt el al. 1999] preferences. and their sexual inter- est in extra-pair males (Gangestad et al. 2002), all suggest a design for seeking good genes during the fertile phase, and some authors claim a petiowlatory increase in extra-pair copulations (Bellis and Baker 1990). Allhough both practical and ethical obstacles make it rlifi'icuit to accurately mea- sure rates of human extra—pair paternity, it is likely that. in all but the most patriarchal soci- eties, sttch conceptions are not rare {Barash and Lipton 2001). Indeed, the existence of both: a) male. physiology suggestive ofa his- lory ofspernt competition. and h) panhuman psychological mechanisms that motivate men to attempt to regulate the sexual behavior of their partners suggests that female extra-pair copulation has constituted a significant selec- tion pressure on males over the course of lmman history (reviewed in ('ireiling and Buss 2000: Barash and Lipton 2001). Hence, rather than constituting nonfunctional ves- tiges inherited from ancient solitary mant- mals, it is likely that psychological mecha~ nisms motivating a periovulatory nadir in feeding and a periontlatory peak in ranging behavior were maintained {and perhaps refined} in humans because of the fitness advantages that ancestral women could reap by shopping for mating alternatives. Conctnsron l have argued that the periovulatory nadir in human feeding is best understand as the product of evolved mechanisms that reduce the satiation threshold in one goal system (for— aging) in the service ofajluwing time for the pursuit of another goal {mating}. Together with the recognition that modern societies may constitute a source of evolutionary dis- equilibrium, this hypothesis generates a num- ber of discrete testable predictions, as follows: 1) Because a readily available and virtually inexhaustible supply of food is likely to exag- gerate the influence of cultural and other exogenous factors on meal size. the periovn- latory nadir in feeding shmtld be more marked in societies where food is less abun- dant. Votutvtr 78 ‘2} Because hoth vehicular transport and virtual travel via print and electronic media are likely to reduce the periovulatory peak in locomotion. cyclical changes in this and related motor activities should be more pro— nounced in societies where women. though able to travel relatively freely, lack ready access to such technology. ti) Because locomotory activity is probably motivated by highererder subjective changes. interest in new experiences. feelings such as ‘Wanderlust” and “cabin fever," and a desire to meet new people (particularly men) should peak armind ovulation, 4-) Because the periovulatory nadir is potentially costly in that it can create a tem- porary energetic deficit, if the utility of the nadir derives from the time that it frees up for mating relevant activities, then for a given individual there should be a correlation between the value of Lhe latter and the extent of the former. Accordingly holding constant physiological variables such as age, health, cycle regularity, and body mass index, and also holding constant environmental vari— ables such as access to vehicular transport and mass media. across subjects, the magnitude of the periovulatory feeding nadir should cor- relate with the extent of increases in loco- rnotory activity and/or the psychological con— comitants thereof (see #3, above). BROA DER IMPLICATION 5 Because the actions entailed by various fitness-enhancing objectives are often incom- patible with one another, a crucial feature of adaptive behavior is the ability to prioritize goals. In many species. the cyclical nature of fecundahility has led to the evolution of mechanisms that regularly rearrange the pri- ority of various goals so as to maximize the likelihood ol'optitnal matings during the fer- tile period. 'l'raditionally. theorists have (implicitly or explicitly) conceptualized this reprioritization as consisting of: a) a rise in the prominence of a specific motivation or drive {i.e.. an increase in libido), and/or h) a change in the salience and/or hedonic valence of some cue (i.e.. heightened atten- tion and attraction to primary and second- M ARCH “2003 ary sex characteristics]. While this view is undoubtedly correct. the evidence regard- ing periovulatory changes in ingestion indie cates thatcyclical reprioritization is achieved not only by increasing the motivational salience of one goal or cue, but also by actively decreasing the motivational salience ofgoals or cues that entail competing behav- iors. It is possible that natural selection fre— quently produces such coordinated enhance- tnent and depression of mechanisms that serve incompatible objectives. For example. the. same time allocation conflict between for- rig-int)J and mating that Forms the core of my argument here may also provide an ultimate explanation for the reduction in male libido that occurs during dramatic dietary constric— tion (cf. Keys et a1. 1950). Furthermore, it is lilter that such coordinated enhancement and depression is not limited to questions of time allocation. For example, in male. mice, exposure to the odor of a novel estrus female increases locomotorv and searching activities. behaviors that are at odds with predator al DA PIA HUN AM!) PEMOl-’L.FL.-”l TORY BEHA l'TOin L CHANCE l 7 avoidance strategies. Kavaliers, Cllolcris. and Colwell {5200]} recently demonstrated that brief exposure to such odors also causes reductions in: a} aversion to predator odors, b) defensive analgesic responses to predator odors, and c) hormonal stress reactions to predator odors. Apparently, because of the overwhelming fitness value of reproduction, the incompatibility between mate—finding behavior and predator avoidance is resolved in favor of the former through a clownregu— lation of mechanisms that subserve the latter. 'l'hese observations suggest that a useful heu~ ristie in the investigation of any given adap~ tive. behavior. psychological state or goal may be to first consider what other behaviors. states. or goals are incompatible with the tar- get. and then explore. the. influence. ot‘rhe for- mer upon the latter and vice versa. .‘H ZKNUW'I.l-'.D[ll\1|-lN'l‘i-l l thanl-rlcnuiier Fessler for stimulating discussionson the topic" Tiara Delgado for research assistance, .‘tnna Ileilig and Robert Kurzban for technical assistance. and an anonymous reviewer l'or helpful t'eedhaclt. REFERENCES Abraham 5 F, Betnnout P Argall Haywood P. 1981. Nutrient intake and the menstrual cycle. Australian C? New Zealmtdfimmdi of starts-m ll: 210—211. Adams B A 1985. The eifect of the human men- strual cycle on kilocalorie and nutrient intake [MS thesis]. Blacksburg (Wit): Virginia Poirreehnie Institute and State University. r'thienius 5. 1993. Brain monoaniinergic neurotrans- mission in the mediation of lordosis behavior in il'lf' Female. I'fil. Neuroscienu’ EST: Hinbrrr'unriimrf Ran-rut} 1?:43—49. Alberti-Fidanza A. Fruitini D, Servili M. 199s. Gusta- torv and food habit changes during the menstrual cycle. fntmarinrtaijonmm’ for thmin and Nutrition Research 68:149—153. Alien 5 b‘. Hatsnkami D. Uht'isiianson D, Brown 5. mini]. Energy intake anti energy expenditure dur— ing the. menstrual cycle in short-term smoking ces- sation. Addictive definition 95:559—572. Altmann M. Knowles E. Bull [1 D. 194]. A psychoso- matic study of the sex cycle in women. Psychosomatic [lift'd‘lflfll' 3199—225. Arletti R, Benelli A, Bertoiiui :‘L 1589. influence of oxytocin on l'eerliug behavior in the rat. Fijihrter 10:89—93. Arne}; D R, Kim's-ed 5 E. Phillips C] C. 1994. The increase in activity durng oestrus in dairv cows. Applied Animal Behaviour Sosa re 40:21 1-218. Aujar'l'l F. Heisli-imauu M, Thierry B. Hodges K. 1998. Functional significance ('Il‘ behavioralr [nor- phological, and endocrine correlates acrtiiss the ovarian cycle in seinih'ee ranging li-im'ile '|,l'_|l|kt"i-_l'|l macaques. .4 nwrimn Iflfllf‘fllfitr of Fri-emitan 45:28:71— 309. Bagdy G. 1995. Role ol‘ the hypothalamic paravenlri— eular nucleus in 5—HT1A. 5-1 iTi’A and 5-I1T9C receptor-mediated oxvtocin. prolaetin and A( THE cot'lit'osteroue responses. Sentimental Brain Research 73:27T—38fi. [larash D P, Lipton] E. 2TH”. 'i'ite fir'fl't'hif. (fifinnogamy: Edam} and Infidelity in. Animals we! Paws]. New York: Vi". ll. Freem an. Bauml E ii. [989. ()n the relationship between the menstrual cycle and the bod}- weight and food intake oi women. :‘orfiii‘trjur Rorianiugiir [41:23?— 250. Hebrem‘ls P. Duly M. Wilson M l. 1936. Range use pat— terns and spatial relationships of Melrialn's kan— garoo rats [Dipodomjs Historian]. Britannia-tn 96: l 37— 209. Bellis M .-\.. Baker R R. [1190. [)0 females promote sperm IsuulpeliLionF—Llata tor humans. Elm—ma! Behonirmr 40:99 7—999. 18 HIE QUA H'IFRIXREWEW OFBIOLOCY Benelli A. Poggioli R. Luppi l’. Ruini L. Ber-tolini A, Arlen] R. 1994. ny‘lut‘ill enhancea and nxytoein antagonism decreases. sexual receptivity in intact iemale rats, Nmnnupinirs 27:245—25fi. Bennett A C. 199-1. Cellnparison of energy intake in use”: unrl non-users oforal contraceptives 1M5 the- sis]. Memphis {TN}: Memphis State University. Bernstein [ L. Zimmermanj ti, Czcisiet E A, Weitz- man E D. 195]. Meal patterns in "free-running" humans. Physiology and Behavior 2?:5‘23—523. Bielcrt (J. Busse (I. [933. Influences of ovarian hor- mones on the food intake and feeding of captive and wild Female clmt‘im‘t iinlmons { Papi'n tinnitus). Physiology rend Behavior 30: 103—1 1]. Hillings F. G. [934. The occurrence oi'cvelic variations in motor activitv in relation to the menstrual cycle in the human female. Bottom q‘rn-fimm Hopkins Hospital 54:440—454. Blausteinj D. Wad-t: (J N. l‘JTIE'i. Chau‘hnl influences on the meal patterns of female ritls. Flemming} and Behavior l7r2fl l — ENS. Bum-mirth R, Poppitl S l). McDevitt R M. Prentice A M. 1995. Food intake and the menstrual cycle: a retrospective analysis. with implications for appe- tite research. Physiology anstito-uior 53:“167—1077, Caplan P. 1996. Why do people eat what they do? Approaches to food and diet from a social science perspective. (Elmira! Child Pounding}.- Psytslntnrj Him—22?. [Iliuppell S, Huckuuv A (i. 1997. Assrntiations between menstrual cycle- t‘il’iaster physical activity level and dietary Inarrontilrit-nt intake. Hieiegv of Sport 14: 251—258. Lilli-islet] (‘2, Mrflnnl H R. ll-li-il. Activity level across the Inenslt Iml cyrle. Poona-vial {9" Motor Skills T2794. Clark] T. 1992. Benextrarnine, a putatiw: neuropep- tide Y receptor antagonist, attenuates the termi- nation of receptivity. Phariuiom- and Behavior 52: 965—969. Clavton A ll. Clavet G]. McC-arvev E 1.. Warnocltl K. Weiss K. 1999. Assessment ui' sexual j'uneu'oning during the menstrual cycle._{eumrxi affix and Mar- tini Therapy 25:281-291. Quezon U. 1990. Serotonin and appetite. Annett- a} the N .' limit Armlqu of Sonatas GOGIDEI {33] . Citttl'cIJ A. [9733. Food rejection in- l'eiuale rhesus IlllJl1' keys during the [menstrual cycle and early preg- nancy. PEJ'SI'UJUKV and Birfirnriw' l-1:5'i'9—fi3'7. [:niilj'dj A, Guy R W. 1975. Ovarian hm‘mones and food intake- in Female guinea pigs and rhesus monkeys. Hmvmmm and Behavior 5:329—34‘3. Danielsen]. Buggy]. 1980. Depression of ad lib and attg-iotensin-induced sodium intake at oestrus. 3min Harem-tilt Bartlett's: 5:5U1—5U4i. Danker-Hopfe H. Hoczcn K. Lowenstein-Wagner U. iiiilr'i. Regulation oi'iood intake. during the men— strual cycle. A nihmprilflgt‘srhrrfi Hanger 53:231—238. VOLUME 78 Del’mn M. 1992. The effects of the menstrual cycle and smoke status on resting energy expenditure. dietary intake. and physical acLiviiy [MS thesis]. Memphis [TN]: Memphis State University. de Castro M. I'J'J'l. Weekly rhythms of spontaneous nutrient intake and meal [Jaltcrn ofhurnans. Phys- iology and. Hammer 50:729A?33. de Castro] M, Bellini: F, Feunekes G I], Dalia A—M. De GraafC. 1997. Culture and meal patterns: a com- parison of the food intake of free-living American. Dutch, and French students. Nutrition Research 17: HGT—829. Donovan B T. 1985. Wheel-running during anoestrns and oestrus in the ferret. Phjsuu’ugj and. Bentham 34:325—829. Duty R 1., Silverthorne. (L. 1975. Influence of men- sirttal cycle on volunteering behaviour. Nature 254:]39—140. Drewen. R F. 191'3. Destrous and diocstrous compo- nents of the ovarian inhibition on hunger in the rat. Animal Behaviour 2 l :1'72—780. Drewctt R F. 1974. The meal patterns of Iht' oestrous cycle and their motivational significance. Qitet'rio'l'j Jaumni afExfm’tmml' Psychology 26:439—494. Dye L. Blundelij E. 1997. Menstrual cycle and appe- tite control: implicaliritts for weight regulation. Human Hrfrt'mfur-tin-u 12:1 [42—1 15]. Et'lt l_. H, Bennett A G, Egan H M, Ray] 'W, Mitchell C 0, Smith M A, Klesges R C. 1997. Differences in macrortutrient selections in users and nonusers of an oral contraceptive. Americanjoumei of Clinical Nutrition 65:419-424. Eckel L A, l-Ioupt T A. (Scary N. 2000. Spomanee-US meal patterns in female rats with and without access to running wheels. Physiology and Behavior 70:397—405. Engeli I). 1985. interdependency 01' food and water intake in humans. Appetite IU:133—l4l. Ferraro R. Lillioja S, k'ontvieille fit M. Rising R. Bogar- dus (J. Ravussin E. 1992. Lower sedentary meta— bolic rate in women compared with men.Jaurnei of Clinical Investigation i'JUfiBU-‘i’tH. Fitzgerald M [-L l'J‘JU. The interplay of culture and symptoms: menstrual symptoms HIIIUIlg SilIflU'dIIS. Manual Amhm‘fmllugy l22145—l (:7. Flowers B. 1997. Detection of estrus. Sarina Nam 2'0. lllil):;",/rnat knsci .ncstterlu/swi ne_news_/l 99?,‘sn_ vEOflfllihn. Fang A K, Kretsch M]. 1993. Changes in dietary intake, urinary nitrogen, and urinary volume across the menstrual cycle. American fountat of (:iinimi Nutrition 57:43—45. Forbes] M. 19?]. Physiological changes affecting vol- untartr food. intake in ruminants. Worsening: offing Nutrition Society 30:135—142. Fracltiewicz 1:: J. Shiovio: 'l‘ M. EUU]. Evaluation and management of premenstrual syndrome and pre- MARth 2003 nn-nsl I'nal rlt'sphorit' disorder. fmtmnt “tilt? :1 men'- rrnn Pltizrnntrenttmt rlssor‘trtttmt 4 [:437-447. lit-lend D W. 1919.. Self-selection 0t teetls and water by [inbred gilts.l,tmtmnt (grim-mitt St'n‘nr't' 37zl l 3T—l l-‘ll. Frost l’. lll'J-‘t. Preference fin tla‘n'ltm fares in photo— graphs at different phases tnl'1he menstrual ryele: preliminary assessmenl nl' e't-‘irlenre for a hor- nmnal relnlnnnship. Penepttmt {7" Motor Hit-tilts 79: 507—514. (‘Iangestad 5 W. Thornltill l1. liltltl. Menstrual cycle variation in women's preferences for the scent uf svmmetrieal men. Hermit-aga- rtj the Royal Soot-i}- at Land”?! Series B 265:1]2'3—933, Gangestarl S W. 'l'hornhill R. {Lars-er t'.‘ E. 2002. Changes in women's sexual interests and their partners‘ mate—retention tiltlit'h nt'rnss the turn- strunl cycle: Evillmlt‘t‘ for shilling rnntlit’l}: nt'inter— irsl . t‘t'nt.nmtin.gs fifth.» lineal Snort)! (JILG’MIIUH Series B 2Ei9:975—9H2. Gare}- Morgan M A. thliehl. Melts-en B 5. Half I) W. 2001. Effects of the pitytnestrugen countes- trnl on loeomotor and tear-related behaviors in female mice. Hormunrr 6T" Behavior attififi—i’fi. Genre N. tlltlEs. The efiect of estrogen on appetite. itftrtsrrtpr Warrants Health 3:?» {leans- N. L’tllll. Fslrarlinl. ("III-i anrl satiation. Prifitt'dst iiilafil—lflliil. Citing F. Garret l]. (iatluwat' D H. 1999. Menstrual eycle and. voluntary l-DIJLl intake. .4 moire-njmrm-ril' :th ti'lrmr'nl Numth 19:252-253 {fuelling H. Buss D M. 2000. Women's sexual strate- gies: the. hirlrlen rlimensinn m" extra—pair mau'ng. Hnsnnntit} 55' Individual Difli'mtrns 23:929-963. Hackney A (I. Carley C S, Nieklas B]. 199]. Physiolog- itzal responses to submasimal exercise at the mid- Follirttlar. twnlatnry anrl J‘nid—ltlteal phases of the menstrual ryrle. 5mnrttnnnionjuurnnt Ofiiterlt'eine it" Hrt'enre in .‘J'pm‘ta 1:94—98. Harrison (3 R. 2000. Gender and menstrual cycle effects in human spatial cognition [PhD disserta- tinn.] (Ilnnnpaign {IL}: University of illinois at LTrbana-(Ihampajgn. l-iedrielts (I A. 1994. Female sexual :tetivitt' across the. human menstrual cycle. Annual Review afSengsmmit. 5:|22-li'2. Henderson BJ. Whtssell LI. Hit-1'7. Changes in women‘s emotions as a function of emotion valence. sell- tleternl lIlt‘Ll category of premenslfltal distress. and tin}- in the [nr-Inslllml ('yl'lv. Psyrflntugfirnt Riffflfrft 8ti:ltl?E—lf274. Hnnpt K A, Goren B, Hint? H F. Hilrlerhranlj E. IQ'FQ. FJTerrl of sex anti repl'ut'lin'lit-e stnlus ('ll'l snrruse preference. food intake. and body weight of clogs. journal at‘thr .v'tmmmn th'nnn' Msdimi Assay-innth l'H: 1033—1035. Howe J (J. Rtnnpler W V. Scale J 1., ititlli. Energy expenditure by Indirect calorimetry in premeno- ADAPT}! Tith Amt) PLI'IUUL’ULA Tfllll’ BE} M WOHA I. CHANGE 19 pausal women: variation. within one menstrual cycle; Journal {y'NrttrtInmrtt Buir'ttmrii.t£r_'t' 41258—273. jtlllrlstnt Vt" t}, ll"'.i'n'rig'.1t‘i .‘i A, lemmnn (l R, Bergeron K E, Crust-rt A ll. 1994. Energy' regulation over the menstrual cycle. Phi-stating“; and Behavior 56:523—527. _[nnklaas j. Buggy]. 1984. Angintensin-cstrogcn inter- action in female brain reduces drinking and prea- snr respt'inses. .-‘tmm'mn J‘uumnt oj'Phytti-‘Jtegt E47: thi'f—tfll. Kuwaiti-en; M. Cltuleris E.1 {lulwell D D. 20”] , Hl'inl'expn— sure to [entitle Utltjn‘s "t'lnl'n'ilrlt-ns" male mice. by ['L‘LlllL'lllg plt-i'latrn'—im'lnrerl hehm’ioral and her- ntnnal responses. Hm'nmnns Etkhntiirn'401497—5tl9. KrtnniLzJ W'.t',l-i|)l1m_j R,l.indsa}-'K it, Fisele 50.1939. Effects of ovarian hnrnmnes rm eating behaviors, hm‘ly wetghl. anrl glucnregulation in rhesus mon- keys. Hormones CE!" Behavior 33:235—250. Keys A. et a]. l95tl. We.» Biolog- of Human Starvation. Minneapolis (MN): University of Minnesota Press, Kidd}: L} A. HIT}. Variation in physical activity as an indication of estrus in dairy cows. jun-mitt affirm? Sitter: re 50:235—243. Ktleltareaylt liliélrl. Nenruentlucrjne niet‘ltanisnls nnvtliuting I'lnirl inraltn- [lining the. estrnns ryele. Brut-rt Reserve}; Bulletin 12:] 75—E8tl. l.i F. T S. Tsang L 13 Y. Ltti S S It. 1999. Menstrual cycle and voluntary food intake in voting Chinese wmnen. Appetite 33:109—1 18. tissner l, Stevens], lfl'll'skt' l'} A. Rasmussen K M, Slrupp PI]. 1939. Variation in rnergy inlnlce. (hiring the menstrual ryrle: implimtions for food-intake research. American journal of Ctttttr't’tt Num'timt 48: 956—962. Lu 2]. 200]. The relationship between menstrual atti- tudes and menstrual symptoms among Taiwanese wnmen. formed nf'rldmnrmi Nursing 33:62 [—628. [.t'ons l‘ M. Truswell A S, Mira M. Viuard]. Abraham 5 F. t989. Reduction of food intake in the ovula- mry phase of the menstrual cycle. .rtmm'ranharnaf of Clinical Nutrition 491] lfiil—l 153. Mantle Ii, Lneltier 5 H. Engel B. 199?. Predictingoptj- ntal time of insemination in cows that show visual signs of estrus by estimating onset of estrus with pedometers. funnier! efDmltftI 80‘.an 80:1098—1 105. Maefarlane] S. HGT. The effect of oestrus on "free" water intalte in Zebu-type heifers. veterinary Reward BEEN—352. Mahuney [J A, Smith L M. I997. An exercise effect on ITIUIJLl during the menstrual cycle: a prelimiuzu‘y it‘wuslignlinn. histhmt'rrm.’ tiff Penetrating} l3:397—--1D$. Mnrin-Biwns (i l... Knha 5 P. Ulster [l H. 1993. InLnt— wnnirzulai llljfll.'ll¢.1|l HF Ill.'lll'l1|Jl:'|.!1.ltll:' Y antisenl curbs weight gain and feeding. and ilil‘l'fiflsfih the display of sexual behaviors in obese zuclter female rats. Winters Peptides 75-76:327—334. Mathis (I E. _|n]ntson D F. (Ioilier (l. 1995, Food and water intake as functions ol'msouree consumption 20 THE QUA tf'l‘lfi'h’t‘l" REVIEW OF BIOLGGY costs in a closed economv.__fou-mm‘ aftheli‘sfmimmtul Amino- offlshrnrior 65527—5472 MatsumoLtrOtla A, Oda R. lil‘Jl'l. Changes in the activ- it‘llr budget ulcvcling female chimpmvees. .‘l mrrn'rrm flirt-mo! of Primilulngy ‘l-li: l TIT— i {if}. McCunnhy K L, Smiciltlas-Vt’right H. Birch I. L. Mitch- ell 1'} (l, Pircinnn M F. 2002. Food portions are pos- itivelv related to energy intake and body»r weight itt earlv childhood. journal of Pediatrics 140540—347. Metlo N K, Bree M P, Mendelsonj H. 1985. Alcohol and food sellLEtrirninistration by female macaque monkeys its a function of nienslruul cycle phase. Physiology and Bolus-trim .‘liilgl'iQ—Qfil'i. Michell A R. 1975. Changes rul'snrliurn appetite during the estrous cycle m" sheep. Physiology and Bsiiavt'or 14:223—226. Michell A R. 1979. Water and electrolvte excretion during the oestrous cycle in sheep. Quortrrljtllour- no! of'Esm'mrntril Physiology and Cog-note Medical Sa- mces 64:?9—38. Michencr G R. McLean l (l. 1906. Reproductive behav— iour tutti operational sex nilin ill Riclmitlsrnl's grmmtl iluirl'elfi. fl'rtirtmil Beliitirinii'r521743—758. Mniine M I.I Aihers H E. "388. Response. nf'cirttaclian locomotnr activity and the pmestrous luteinizing hormone surge to phase shifts of the lightvdarl: cycle in the hamster. Hljstfllflgj' and Behavior 43: 435—440. Morin L 1’. Fleming A S. [978. Variation ot'loodintalte and body weight with estrous cycle. ovariectnmy. and cstradiol benzoate treatment in hamsters [Menstran animus}. jotth of Comparative rind Physiological Psychologt 9211—6. Morris N M. L'dryJ R. [070 Variations in pedometer activity during the menstrual cycle. Donation and gynecology 35:199—201. Muir L A, Hillst “i. Ctmtutl H R. Smith K l... 1972. Flint Illesll't'lgen 31ml pu.lgehler'tlru' tiltl leel'l il'ilallte and livrirnxvproline esrt'etinn “showing inrlilcetl hypoealremia in rows. jmtrrml of Dori]; Scion”? Eli: 161341620. Murdock G P. 1967. Ethimgmpliin Atlas. Pittshurgh (PA): UniversinJ of Pittsburgh Press. Neuhaus [. C. 1990. Qualitative chzmges in food intake during the menstrual cycle in normal healthy women and mesa with premenstrual syndrome [M5 thesis. J Buli'alo {NY}: State University ofNew York at Bufi'alo. Urtman R. EUUU. Monitorng 01' esrrous circle of ewes by tum-seeking behavior. 3mm“! Ram‘nrmt Researrh 37:73mi’i‘l. Panlissn ('1, Risen M R, Maa.-rir|tti ('i, Rulrintli WII Taglin- monte M R. Varriechio G. Carella (I, Varricrhin M. [999. Lack of association between changes in plasma leptjn concentration and in food intake during the menstrual cvcle. Europsmijounml of Clinical Investigation 29:490-495. VOLUME 78 Pelkninn C L, Chow M, Heinharh R A, Rolls ll]. 20m. Short—term ell-eels oi" a pi‘ngeslntinnal cnntrarep— tive drug on Food intake. resting energy expendi- ture. and body weight. in young women. .‘imm'mn I Journal of Clinical Nutrition 73: I'll—26. Fenton-Voakl S. Ferrell [. Castles D L. KubaynslnT, Burt [J M. Murray L K Mintnnisuwn R. lQQQ. Merl- sll'ilal cycle alters rare preference. hint-ms 5399;741- 7432. Pfafi‘ D W. 1930. Estrogens and Brain Function; Neural Ant-insist of a Hmnonecomrattm illumination Repro- ductive [illiterate]: New York: Springer-Verlug. Rnnn A P. MrAskill] W. Conley C O. 'l'i’agner] F. Ton- ltinsnn L. lFlfiTr'. Effect of estrus and stage of the estrous cycle on feed intake of heifers. journal of Animal Home 26:949—95U. RauLh-Witlmann B. 1989. Synchronisation und mas- lLicrtlrlg Circadiancr rltythtnen vutl Nachtnfien [riot-us iié'TlJ.Ii-'i”li'l'.l'l-.\' giiseirmrtrilri'u) rillrrh l.ii'hl unrl deren hnrmoneile 11nd netllttpharniakolog‘ische Beeinflnssnng [PhD dissertation]. Tubingen (Ger- many): University ol‘Tiihingen. Ranth—Wldmann l5. Fuchs l:'.. Briton. H G. l'J'Jti. infra— dian alteration of circadian rhythms in owl lIlUIJ- keys (drains ermmimn' g’riheimmlmtl: an ell-cc] of estrous:- Pli'v.t-iolrigy and Behavior 59;] 1—18. Regan P C. 1996. Rhythms of desire: the association between menstrual cycle phases and female sexual desire, [floodiortjwmat of Home smarts}: 5:145— lfifi. Rnllin C, Knrharrzflt], [emriineJ, Biehet D, Tsang H K. 1989. Usmnregulatinn nl'vasnpressin secretion and thirst during the estrous cycle of pigs. Ame-imit- journal of Physiology 255:11270-275. Rolls BJ. Eng-ell D, Birch L L. 2000. Serving portion size influences 5—year—old but not 3—year—old chil— dren’s Frlntl inlakefl. jtm-nml tifll'n' Atomic-3m Dietetic Association 100:23‘2—234. Rolls Bl]. 'v'an Duijvenvoorde l‘ M. Rolls E T. 1984-. Plcasanmcss changes and food intake in a varied fouracourse meal. Appetirefifi'j'F—BCIB. Rosenhlall H. Dyreul‘nrlh I, Ferit] M, Vinnie “liele R l.. l98'll. Food intake and the menstrual cycle in rhesus monkeys. Physiology and Behatiim'24:44?~449. Rosin P. Fischlcr L‘. [roads 5, Sarubin A, Wrzesniewski A. 1999. Attitudes to food and the role ot't'ood in. life in the. USA, japan. Flemish Belgium and France: possible implications For the {llfi'l'ilt‘flllll debate. Appetite 33:163—180. Sass-man U 5. [Wt]. the menstrual cycle and sexual behaviour in a lump ul' free winging elutemn baboons [Pa-pin uni-inns). Foliafiimatoiogim l 2:81— 110. Saucier D M. Green .‘i M, [ti-INIJIIJ, Man'Fatltlc-n A, Bell 5. Elias LJ. 2002. Are sex diFferenees in mitigation caused by sexually dimorphic strategies or by clif- lel'ellt'es in the ability to use the strategies? Belmo- iornl himmttimm l [Iii-103410. M »t RCH 2mm Silverntan L C-lttti Nltlcltewu A. Fisltet Xi. MILII'ITI (—Jlsltanslt} E. 2000. Evttlvetl Ittet'ltauisltts underly- ing waylintling: lintltei studies on the hunter- grttherer theory.r of spatial sex Clifl’ltfl‘tl‘ttjtffi. Evolution; 55'" Human l'lréfartirt'm' 21:201-213. Silverntatt I. Eals M. 1992. Sex differences in spatial abilities: evolutionary theory and data. Pages 533- 549 in The Adapted .Mt'nd: Evolutionary Psych trilogy and thy (kite-ration rif'tfitiltttre, edited by] H Bari-tow ct at. Oxford and New York: Utilier University Press. Small M l". l'J‘JES. fit-male (Shrines: Sexual Behavior oermcit'e Pawns. Ithaca (NY): Cornell [Suit-err.in Press. Smith ‘t" R, Kuhn-Ia K, rlel Carmen M (i. Dannnls R F, Rfl'u'f‘ll H T, 7.;trur H A, Frost] IQQR. Brain opioid receptor measuremettL-t ht; positron emis» sion tomography in normal cycling women: rela- tionship to luteinizing hormone pulsatilitt' and gonadal steroid hortttonesJouritat' of Clinicatfindo- missing» and t‘ivt‘etru'ititt'sm 83:44-98-4505. Sophos C M. 1983. Nutrient intake and body weight during the human menstrual cycle [M5 thesis.] Seattle {WA}: Li'nit'ersity of ‘l‘t’ushington. Stenn P I}, Klittge V. 1971?. Relationship between the menstrual cycle and butlin activity in humans. Her urn-mu H'Hflr Relation: 31297—5105. Strassntttnn B l. “496. The evolution of'ettrlotttett'ial cycles and menstruation. Quarterly Rm‘m- afflicting-3' i’l:l$le22tl. 'l'aluthashij 5. Mettaket‘ M. 1980. Interaction (tilestra— diol and. progesterone: cil'ccts on circadian loco- rnotttr rhythm of female golden hamsters. Jimmie-n Journal of Physiology BER-197404. Tartteiin M F. 1963. Cyclical variations in food and water intakes in ewes. jmirmt! ey'Pftystth’ug 195: 291"- .‘i l P. Tfll'lrelil‘t M F. Ct't-t'filti R A. 1971. Variation-s in [bud and water intake in the normal and acyclir female. rat. Physiology and Behavior HEN—852. L'pltoun: l... Caldamla-Paslusaka M. Montanez S. 1992. Intracereitral actions of the 5+th 1A} agottists. 8- UH—DPA'I' and huspjrmte and of the 5+l-ITtlA} partial agonistx'antagonist. NAN-190. on female sexual behavior. Nettrtiphanntrrnfugj 3 l ZUfi‘J—‘JH | . van den Herghe P L 1939. The litmin tutti the hit.)- ADrl PTA Tit'JN AND PEFUOWEA TOR l" BEHH WORiL CHANGE 2 l logical base of'lttttttatt meialiq'. Pages fig—[it’ll in His» 5min! Pie-isfmriinnt H'H the Family, editerl he F. F. Filsin— get: Tltt'iusrtnrl Oaks (CA): Sage Publications. Vit‘kers S P. Clifton P Gr Dottrish C T. Tecott L11. 1999. Reduced satiating' effect of d—fettflttramine in sero- tonin 5-HT(2L'.J receptor mutant mice. I’stlchopfmr- morning; l 43:309—3] 4. \r’irts K. L. 1997. Menstrual cycle-related eating behav- ior in women with and without premenstrual dys- phoric disorder [l’hlJ dissertation]. Nashville (TN): Vanderbilt. University. "rlJ-iilf'i TJ. \Nriss N M, Fit llreihet J, Caskill M B, Ruhr el'tsrtn (i l.. 1933. Ostttm'egulation of thirst and vasopressin (luring normal menstrual cycle. Amm- .i'rmr founml of Physiology 2543Rfi414i47. Wade G N. [976. Sex hormones. regulator}.- behaviors. and body weight. Advances in the Study of Behavior 6:201—279. Wade t‘: chker l. 1971). Modulation of food intake and locomotor activity in tetnalc raLs ht; dicncc— phalic hormone implait L%._Jl'0u3"?ld|i of (.‘(imprtmtitie Cf Physiafagtraz’ Hyr'ftot‘om- $252 8—1536. Wtle M. 1987‘. [)iettu'y intake variations relative to spe- cific menstrual cycle phase [MS thesis]. Amherst (MA): University of Massachusetts. 'Wm‘lg (i H. “3953. The relation between 'spunltuteutts' activity and oestrus cycle in the rat. Cmrtfmmtoie Pet- rrl'mlog't ftd'mmgmphs 2:1—27. ‘Wattsinlt B. 1995. Can package size accelerate usage V‘olllflICPJOLtmflE of Marketing 60:1-13. Webb P. 1986. 24-hour energy expenditure and the menstrual cycle. :1 mm'mn journal of Clinical Num— i't'wt 4%:514—619. Widntaicr E P. Campbell (J S. 1980. interaction ofestm— din] and photoperiod on activity patterns in the female hamster. Phantom and Behavior 241923-930. ‘Wi ill' at, Caltittrtila-Paslttsttlta M, UeLt-tshaw M, Llphougc L. “999. E't-HTflrI receptor involvement in female rat lm’dt‘lfiis hel‘lf—I‘L'ittt', Bruin Rirttart'r'dt82511Jlfi—15J_ Wong B. Parker K l.. 1988. Fsrrus irt blink-tailed deer. fortnier of Momman fig: ltiR—l 7| . Young 1. R. Nestle M. 2002. The contt‘ihution or expanding portion sizes to the US ohesittr epi- dem ie. .-'I m m'rart. formic! qf'Ptt bitt- Hralrh 92:246—249. ...
View Full Document

Page1 / 19

FesslerNoTimeToEatQRB - \-b1.L'Mr. 73, Ni}. I Mn RCH 2003...

This preview shows document pages 1 - 19. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online