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Unformatted text preview: Lecture 19 - Energy Balance and Regulation of Feeding Behavior Calorie values- CArbs (4.1)- Fats (9.3)- Proteins (4.1)- Ethanol (very high! 7.1 of the carbs) Components of total body energy expenditure in a person, not cell *The total body energy expenditure > intake loss weight *Total < intake deposit as TG gain weight- Total energy expenditure = heat produced + work on environment o Physical activity (variable) o Adaptive thermogenesis (variable, regulated by brain; response to temp. and found in brown adipose tissue) o Obligatory energy expenditure (required for normal cellular and organ functions)- How many calories do you need to maintain balance? o Females about 2000-2200 o Males a little more 2400-2800 Thermogenesis- The generation of heat when an organism is at rest and not performing work on the environment- Results from reactions in energy metabolism that are exothermic in the forward reaction (Na + /K + ATPase, Ca 2+ ATPase, actinomysin ATPase) Basal metabolic rate- Term we use to refer to how much energy the body is expending under sets of conditions o Of calorie consumption in a resting, awake in the post absorptive sate (fasting) o Measurements are made in the absence of muscular activity at a comfortable environmental temperature o Roughly corresponds to the obligate energy expenditure required for the performance of cellular and organ functions- This isnt a set constant and varies! o For most individual about 1kal/kg/hour (80 watts)- Basal metabolic rate is subject to regulation o Decrease about 10% during sleep o Decrease about 40% during starvation o Decrease with age (approx 10% between age 20- 60) o Slightly higher in males than females o Key regulator = thyroid hormone a critical regulator) Low thyroid hormone low metabolic rate High = high metabolic rate- Energy expenditure also determined by the physical activity that one carries out!- Physical Activity Levels (PALs) The biggest variable in the energy expenditure equations o Brisk walking (1 hr) 4-5 x BMR o Cycling/dancing (45 min) 6-7 x BMR o Soccer, cross country skiing, running (8 min miles) 10-12 x BMR Adaptive Thermogenesis- Heat production in response to environmental temperature of diet- Generates heat to help protect the organism against cold exposure- Modifies energy expenditure to help regulate energy balance in response to change in diet o This will help your body adjust to the varying diet- Responses to cold o Increased heat production Shivering acute/transient muscle energy expenditure with no work performed Adaptive thermogenesis short and long term Two to four fold increase in O2 consumption in rodents 5-10% increase in humans in the short term, more pronounced in the long term due to increased thyroid hormone production Decreased heat loss vasoconstriction Behavioral changes can do both (exercise, more clothes) - Diet-inducted changes in energy expenditure o...
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This note was uploaded on 09/14/2011 for the course PHARM ERM taught by Professor Staff during the Spring '11 term at UCSD.
- Spring '11