1. Energy Balance and Weight Management: Finding Your Equilibrium BIOL 103, Chapter 8-1

2. Today’s Topics Energy In Energy Out Body Composition: Understanding Fatness and Weight Overweight and Obesity

3. Energy Balance Energy Intake vs. Energy Output

4. Energy Balance Energy equilibrium – Intake ___ output – Maintain weight Positive energy balance – Intake ___ Output – ___________________ Negative energy balance – Intake ___ Output – ___________________

5. Internal Cues that Regulate Energy Intake

6. Energy In – Regulation of Intake (Problem Set #8, Q 1) Internal cues 1._______: prompts eating (e.g. stomach growling) 2.________: Signals to stop eating 3.________: Tells when you are ready to eat again External cue – _______________: psychological desire to eat Influenced by the eating environment (e.g. if you are at a buffet, you might want to eat more)

7. Energy In Key concept: Food intake is regulated by sensations of (1) hunger (a physiological drive to eat), (2) satiation (feelings of satisfaction that lead to ending a meal), and (3) satiety (continued feelings of fullness that delay that start of the next meal). (4) Appetite is the psychological urge to eat and often as _______________________. Question: – Are your internal cues regulated by physiological drive or psychological drive? – How about your external cues?

8. What stimulates our internal/external cues? Control by committee – What factors stimulates our cues? 1.Internal: ____________________________ – Examples: in our GI tract, central nervous system, general circulation 2.External: ____________________________ – Examples: where we are eating, what we are eating, who we are eating with

9. Internal Factors 1.____________________________ – Sense of fullness as the ingested food stretches your stomach/intestine Ex: sushi and water 2.Neurological and hormonal factors – ______________________________: appetite stimulator hormone in the brain Neuropeptide Y activity can be affected by signals from ghrelin and leptin  affects daily feeding pattern __________: stomach hormone that ___________________________ – _______________________________ _____________: a hormone produced by adipose cells that signals brain to _____________________________________ – _______________________________

10. External Factors that affect your Energy Intake 1.___________________________ – Energy density (_______of food) High energy dense food vs. low energy dense food – Balance of energy sources (carbs, fat, proteins) Eating proteins  increase satiety Eating fiber help suppress appetite – Form ___________________ 2._____________________ – __________, texture, color temperature, presentation…

11. External Factors 3.__________________ – Super-size culture, “McDonald’s value meals” – “never ending bowl of soup” 4.Environmental and social factors – Eat more in cold weather, eat less in hot weather Why? – _________________: region in our brain that regulate hunger and satiety, respiration, body temperature, water balance, and other body functions. – More people in the group  longer meals  eat more by 30% 5.__________________ – Eating to cope with stress, low self-esteem, boredom, low energy levels

12. Energy In: Regulatory Factors

13. How do our bodies use energy? 1.Maintain basic physiological functions such as breathing and blood circulation (Resting energy expenditure or REE) 2.To process the food we eat (thermic effect of food or TEF) 3.To power physical activity (PA) REE + TEF + PA = ___________

14. Energy Out: Fuel Uses Major components of Energy Expenditure: 1.Resting Energy Expenditure (REE): __________________ ____________________________ – Examples: breathing, heart beating, respiration, muscle tone, body temperature, etc. Affected by body size, composition, age, and gender 2.Physical Activity (PA): energy spent during leisure, work, and exercise ____________________________ Affected by body size, fitness level, and type of activity 3.Thermic Effect of Food (TEF) Energy to ________________________________ – Foods that actually burn calories (usually contain more water than sugar; contain fiber): celery, grapefruit, watermelon, lettuce, hot chili peppers, tomatoes, lemon, etc. (This is just FYI)

15. How to Calculate your TEE Estimating total energy expenditure: – Resting energy expenditure (REE) Males: 1.0 kcal/kg/hr Females: 0.9 kcal/kg/hr ________________________________________________ – Physical activity Estimated by how much an individual with a certain amount of body weight exercised in a given time Refer to Table 8.2 – Thermic effect of food 0.1 x (REE + physical activity)

16. Estimating Energy Expenditure Just as there are DRIs for nutrients, there are also DRIs for energy, called _______________ _____________________________________ – Definition: energy intake predicted to maintain energy balance in a healthy person of normal weight – Equations for males and females Factors for age, weight, height, and physical activity – Predicts ________________________________ See Table 8.4 for more details

17. Body Composition: Understanding Fatness and Weight Body composition – Is the relative amount of fat and lean muscle mass – Muscle is ______________ than fat Assessing body weight – _______________________________________ BMI ≤ __________= underweight BMI ___________________= normal weight BMI ___________________= overweight BMI ___________= obese –Q: Does BMI indicate how much fat you have?

18. Problem Set 8, Question 2 BMI = 704.5 x [weight (lb)/height (in 2 )] REE for women = (weight in kg) x 0.9 x 24 REE for men = (weight in kg) x 1.0 x 24 TEF = 0.1 x (energy from physical activity + REE) TEE = REE + energy from physical activity + TEF

19. How to measure body fatness? Can do this because fat and lean tissues have different densities 1._____________: Dual Energy X-ray Absorptiometry – Pros: Measures bone, fat mass, lean body mass (protein and water) – Con: too expensive 2.______________________________________ – Q: If 2 people with the same weight but different levels of fat were weighed in water, who would weigh less? 3._____________ uses displacement of air to measure fat vs. fat-free mass 4.______________________ uses calibers to pinch “fatty” tissues and add them up – Better practice to measure for malnutrition than for obesity 5.______________________ uses electrical charge to run through lean mass and fat. Lean tissue has more water = better conductance. – Con: if subject is dehydrated  inaccurately high levels of fat are estimated

20. Overweight and Obesity Overweight/Obesity is a major public health problem – A global problem US: __________ of American adults are overweight/obese – Affects adults and youth – Healthy People 2020 goal: _____________ the proportion of adults, adolescents, and children who are obese

21. Factors in Development of Obesity 1.Biological: 1.Genetic/heredity 2.Fat cell development: number and size of fat cells help determine how easily a person gains or loses fat. Hypercellular obesity: obesity due to an _____________ ______________________________ Hypertrophic obesity: obesity due to an increase in the ______________________________ Hyperplastic obesity: obesity due to an increase in ____________________________________________ 3.Sex and Age 4.___________________________

22. Factors in Development of Obesity 2.Social and environmental 1._________________________ (ex: periods of overeating in food insecure families, rural vs. city life) 2.__________________________: “human formed, developed, or structural areas” Ex: safer vs. more dangerous neighborhoods, work environment (Google offices with fitness gyms and chefs) 3._____________________ (ex: family/friend may choose the restaurant, “pizza night” every Fridays) 3.Lifestyle and behavior 1.___________________ (ex: lack of exercise) 2.___________________(ex: restrained eaters, binge eaters)

23. Overweight and Obesity Health risks of overweight and obesity – Heart disease, stroke, diabetes, hypertension, metabolic syndrome, cancer, gallbladder disease, joint disease, and sleep apnea Weight cycling or “yo-yo dieting”: _________ _____________________________________ – Associated with negative effects on health risks, body composition, body fat distribution, and energy expenditure. – Prone to future weight gain