Energy Balance and Weight Management: Finding Your Equilibrium

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

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

3. Energy Balance • Energy Intake vs. Energy Output

4. Energy Balance • Energy equilibrium • Intake = output • ______________ weight • Positive energy balance • Intake ___ Output • Gain weight • Negative energy balance • Intake ____ Output • Lose weight

5. Energy In • Key concept: Food intake is regulated by sensations of • Hunger: a physiological drive to eat • Satiation: feelings of satisfaction that lead to ending a meal • Satiety: continued feelings of fullness that delay that start of the next meal • Appetite: the psychological urge to eat and often as no relation to ___________________. • Question: • Are your internal cues regulated by physiological drive or psychological drive?

6. Internal Cues that Regulate Energy Intake

7. Why does our stomach growl? • Stomach growling can happen any time, but with food, it becomes quieter. • Empty stomach  stomach produce hormones that stimulate local nerves to send a message to the brain  brain signals digestive muscles to restart the process of peristalsis  contractions occur to sweep up any remaining food AND vibrations in your stomach occur to make you feel hungry.

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

9. Internal Factors • Gastrointestinal sensations • Sense of fullness as the ingested food stretches your stomach/intestine • Ex: sushi and water • Neurological and hormonal factors • Neuropeptide Y • Neuropeptide Y activity can be affected by signals from ghrelin and leptin  affects daily feeding pattern • Ghrelin: “_______________ hormone” from stomach • Leptin: “_______________ hormone” by adipose cells

10. External Factors that affect your Energy Intake • Diet composition • Energy density (kcal/g of food) • Balance of energy sources (carbs, fat, proteins) • Form (liquid vs. solid) • Sensory properties • Taste, texture, color, temperature, presentation…

11. External Factors • Portion size • Super-size culture, “McDonald’s value meals” • “never ending bowl of soup” • Environmental and social factors • Eat more in cold weather, eat less in hot weather • Why? • Hypothalamus • More people in the group • Emotional factors • Eating to cope with stress, low self-esteem, boredom, low energy levels

12. Energy In: Regulatory Factors

13. How does our bodies use energy? Resting energy expenditure or (REE) Thermic effect of food (TEF) Physical activity (PA) REE + TEF + PA = Total Energy Expenditure

14. Energy Out: Fuel Uses • Major components of Energy Expenditure: • Resting Energy Expenditure (REE) • Energy for basic body functions • Affected by body size, composition, age, and gender • Physical Activity (PA) • Highly variable • Affected by body size, fitness level, and type of activity • Thermic Effect of Food (TEF) • Energy to digest, absorb, metabolize food

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 • REE = weight (kg) x [ ______ kcal/kg] x 24hr/day • 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 Estimated Energy Requirement (EER) • 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 total energy expenditure (TEE) • 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 • Body mass index (BMI) = Weight (lb) x Height2 (in) • BMI ≤ 18.5 kg/m2 = underweight • BMI 18.5 to ≥ 25 kg/m2 = normal weight • BMI 25 to ≤ 30kg/m2 = overweight • BMI ≥ 30 kg/m2 = obese • Q: Does BMI indicate how much fat you have?

18. Problem Set 8, Question 3 • BMI = 704.5 x [weight (lb)/height (in2)] • 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 • DXA: Dual Energy X-ray Absorptiometry • Underwater weighing • Q: If 2 people with the same weight but different levels of fat were weighed in water, who would weigh less? • BodPod • Skinfold measurements • Bioelectrical impedance

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: to reduce (by 10%) the proportion of adults, adolescents, and children who are obese

21. Factors in Development of Obesity • Biological: • Genetic/heredity • Race and Ethnicity • Fat cell development: number and size of fat cells help determine how easily a person gains or loses fat. • Hypertrophic obesity • Hyperplastic obesity

22. Hyperplastic vs. Hypertrophic • Biological, continued… • Sex and Age • As children: boys are less likely than girls to consider themselves overweight • As adults… • Men: men see themselves as overweight at higher weights • Women: women see themselves as overweight at healthy weight • Men/Women tend to gain most weight between 25-34 years of age

23. Factors in Development of Obesity • Social and environmental • Socioeconomic status • Built environment • Social factors • Lifestyle and behavior • Physical activity (ex: lack of exercise) • Psychological factors (ex: restrained eaters, binge eaters)

24. Overweight and Obesity • Health risks of overweight and obesity • 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

25. Weight Management • Weight management is the adoption of healthful and sustainable eating and exercise behaviors indicated for reduced disease risk and improved feelings of energy and well-being.

26. Weight Management • The perception of weight • 1960s: thin was “in” • Multiple factors contribute to obesity: genetic, psychological, metabolic, hormonal, environmental, behavioral, sociocultural • Health professionals emphasize _________________ and f_________________

27. Weight Management • What goals should I set? • Set realistic and attainable goals • Aim for metabolic fitness than a specific weight • Metabolic fitness: the absence of all metabolic and biochemical risk factors associated with obesity

28. The Perception of Weight

29. Diet and Eating Habits • Total calories • Limiting portion sizes or reducing total calories intake • Crash diets don’t work • Highly restrictive diet = not long-term • Starving a meal can actually make you hungrier  eat more!

30. Diet and Eating Habits • Balancing energy sources: fat, carbs, and protein • Fat: 20-25% of total calories • Eat healthy sources of fat (PUFA) and fiber to delay satiation • Carbs: 45-65% of total calories • Low sugar foods (ex: fresh fruits) • Protein: 10-35% of total calories • Eating habits • Regular Physical Activity

31. Thinking and Emotions • Balancing Acceptance and Change • Initial weight loss: ___________ loss • Weight loss then can slow down to a plateau of ____________ lb/week • Initial loss = fluid loss • Later loss = fat loss

32. Weight Management Approaches • Self-help books • Watch out for signs of a fat diet • Warnings: “quick and easy,”“scientific breakthrough” • Meal replacements • “Slim-fast” diet • Self-help groups • Help cope with weight

33. Weight Management Approaches • Commercial programs • 1970s: Very-low calorie diet • Professional counselors • FDA-approved weight-loss medications • Appetite suppressants • Lipase inhibitor • Effect is modest; still encourage exercise + low fat food.

34. Weight Management Approaches • Over-the-counter drugs and dietary supplements • Does not need FDA approval before marketing • Pills of caffeine, fiber (dehydration), benzocaine (numbs tongue to reduce taste sensations) • Surgery (BMI >40) • Last-ditch effort • Gastric banding (stomach stapling) • Gastric bypass

35. Gastric Bypass + Banding

36. Weight Management Approaches • Surgery, cont…. • Liposuction: not highly effective because body still has visceral fat, ready to store extra fat • Risks: blood clots, perforation injuries, skin, nerve damage, etc. • Surgery should be complemented with exercise and a healthy diet. • Maintaining healthy eating habits is very important!

37. Underweight • Causes and Assessment • Altered responses • Eating disorders factors • Metabolic and heredity factors • Prolonged physical and emotional stress • Addiction to alcohol and street drugs • Bizarre diet patterns

38. Underweight • Weight gain strategies: • Small, frequent meals • Fluids between meals • High-calorie foods and beverages • Timers or other cues • similar to ABC model • Vitamin/mineral supplements