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Unformatted text preview: Lecture 21: Environmental Eating I. ENERGY BALANCE: Focus on control of energy intake. 1. Dominant theories in area: a. Biological - We eat because we have a biological signal that tells us to do so. i. Argument doesn’t hold up – a lot of good evidence against it has been formulated. II. REVIEW FROM PREVIOUS LECTURE: Evidence: Biological Theory of Eating 1. No feedback from fat has been identified. 2. Biological signals are not specific for eating behavior. 3. Small yearly energetic error does not mean there is physiological regulation. 4. Humans don't respond to food deprivation by overeating. III. EVIDENCE FROM THIS LECTURE 5. Humans don't respond to overfeeding by eating less. a. Overconsumption i. Study: Levitsky et al. (1985) - Caloric Intake (kcal) vs. Days was studied and plotted 1. Baseline (control) period of normal caloric intake was recorded for two weeks, then was followed by forced overfeeding period (1/3 more calories per day). After this period, there was a recovery period where students could go back to eating as they wanted. a. How much will students eat after overfeeding period? 2. After period of overfeeding, caloric intake went back to before period of overfeeding (recovery period caloric intake went back to baseline caloric intake). 3. Note: Students still lost weight during recovery period, though they did not eat less than normal. 6. Humans don't compensate for changes in energy density of food by changing their intake a. Changes in Energy Density: Easiest way to change density is to change the amount of fat. i. Study (Ann Kinsella) - Intake (Kcal) vs. Time (weeks) plotted, with two different groups 1. Same diet for both groups (same volume of food), except that first group had 35% cal as fat, second had 25% cal as fat 2. Slight upward intake trend in both groups as time passed 3. Kcal intake in 35% cal as fat group was greater than 25% cal as fat group; 25% group intake never caught up to 35%...
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This note was uploaded on 04/03/2008 for the course NS 1150 taught by Professor Levitsky during the Fall '05 term at Cornell.
- Fall '05