Weight Management and Energy Balance Chapter 10 Weight Management and Energy Balance

Objectives for Chapter 10 Explain the concept of a healthy weight. Define and describe the concept of energy balance. Discuss what happens to the body if too many or too few calories are consumed. List factors that often contribute to higher body weight. Describe a basic plan for healthy weight loss and/or weight gain. Modern Dieting: Fads and Methods Eating Disorders

1. What Is Weight Management and Why Is Maintaining It Important? Healthy weight is one that doesn’t increase the risk of developing weight-related health problems and diseases Overweight: 10 to 15 pounds more than healthy weight 67 percent of Americans are overweight Obesity: 25 to 40 pounds more than healthy weight 34 percent of Americans are obese

1. What Is Weight Management and Why Is Maintaining It Important? Being overweight increases risk of hypertension, stroke, heart disease, gallbladder disease, type 2 diabetes, osteoarthritis, some cancers, and sleep apnea Losing as little as 10 to 20 pounds reduces risk Underweight: weighing too little for your height May be caused by: excessive calorie restriction and/or physical activity, underlying medical condition, emotional stress At risk for low body protein and fat stores and a depressed immune system (particularly elderly) 4

1. How Do You Know If You’re at a Healthy Weight? Measure your BMI: Body mass index (BMI) = weight (lbs) x 703 height squared (in2) BMI > 25 is overweight: modest increase in risk of dying from diseases > 30 is obese: 50 to 100 percent higher risk of dying prematurely compared to healthy weight < 18.5 is underweight, can also be unhealthy 5

1. What’s Your BMI? Figure 10.1 6

1. Visceral and Subcutaneous Fat Storage in the Body Figure 10.2 7

1. How Do You Know if You’re at a Healthy Weight? Measure your body fat and its location: Average healthy adult male between 20 and 49 years of age: 16 to 21 percent of weight is body fat Average healthy female: 22 to 26 percent body fat Techniques for measuring amount of body fat: skinfold thickness measurements, bioelectrical impedance, dual-energy X-ray absorptiometry, underwater weighing, and air displacement Central obesity (excess visceral fat) increases risk of heart disease, diabetes, and hypertension Measure waist circumference 8

1. Table 10.1

1. How at Risk Are You? Figure 10.4 10

2. Can You Be Slim and Obese? Hidden Risk of Normal Weight Obesity http://abcnews.go.com/GMA/HealthyLiving/video/sneaky-fat-9674189 Discussion Questions How can a person who is “normal” weight be at risk for obesity-related diseases? In addition to increased percentage of body fat, what characteristic of body fat points to increased health risks?

2. What Is Energy Balance and What Determines Energy Needs? Energy balance is calories in versus calories out Positive energy balance: consume more calories than expend, leads to fat storage, weight gain Negative energy balance: calorie intake falls short of needs, leads to weight loss Energy needs are different for everyone Energy needs comprised of: Basal metabolism Thermic effect of food Physical activities 12

2. Energy Balance and Imbalances Figure 10.5 13

2. The Three Components of Your Energy Needs Figure 10.6 14

2. What Is Energy Balance and What Determines Energy Needs? Your BMR will increase your energy needs Minimum energy needed to keep you alive (meet basic physiological needs) Makes up about 60 percent total energy needs Many factors affect BMR (Table 10.2) The thermic effect of food affects your energy needs. Amount of calories expended to digest, absorb, and process food (about 10 percent of calories in food eaten) 15

2. Life is not Fair! Table 10.2 top 16

2. Life is not Fair! Table 10.2 bottom 17

2. What Is Energy Balance and What Determines Energy Needs? Physical activity will increase your energy needs Sedentary people expend less than ½ energy of BMR in physical activity Very active athletes can expend twice BMR Exercise causes small increase in energy expenditure after activity has stopped Calculating your energy needs: Estimated energy requirement (EER) of DRIs provide estimate for various groups Can calculate EER based on height/weight/age 18

2. 19

3. What Are the Effects of an Energy Imbalance? Too few calories can cause underweight Stored glycogen and fat are used as fuel sources Amino acids from body protein breakdown can be used to make glucose Liver glycogen depleted in 2 to 3 days Ketone bodies generated from incomplete breakdown of fat Fat stores and about 1/3 of lean tissue mass depleted in about 60 days, resulting in death 20

3. What Are the Effects of an Energy Imbalance? Too many calories can cause overweight Excess calories stored as fat, regardless of source Limited capacity to store glucose as glycogen Can’t store extra protein Unlimited capacity to store fat Body contains about 35 billion fat cells, which can expand 21

4. What Factors Are Likely to Affect Body Weight? What and how often you eat, physiology, genetics, environment all play role in weight management Hunger and appetite affect what you eat Appetite is psychological desire for food Hunger is physiological need for food, subsides as feeling of satiation sets in Satiety determines length of time between eating episodes 22

4. What Factors Are Likely to Affect Body Weight? Physiological mechanisms help regulate hunger Many hormones play role: Ghrelin: produced in stomach when empty; increases hunger When fat stores increase, leptin in fat tissue signals brain to decrease hunger and food intake. Cholecystokinin: released when stomach is distended, increasing feelings of satiation, decreasing hunger Protein, fatty acids, and monosaccharides in small intestine stimulate feedback to brain to decrease hunger Insulin also causes brain to decrease hunger Many people override feedback mechanisms, resulting in energy imbalance 23

4. What Factors Are Likely to Affect Body Weight? Genetics partially determine body weight Risk of becoming obese doubles if parents are overweight, triples if obese, five times greater if severely obese Confirmed by studies of identical twins separated at birth 24

4. What Factors Are Likely to Affect Body Weight? Genetic differences in level or function of hormones, such as high ghrelin or low leptin levels, increase obesity. Many obese have adequate leptin but brain has developed resistance to it Genetic differences in nonexercise-associated thermogenesis (NEAT) (rate of energy expenditure in fidgeting, standing, other nonexercise movement) “Set point” theory holds that body opposes weight loss and works to maintain a set weight 25

4. Environmental Factors of Weight Gain Figure 10.7

4. What Factors Are Likely to Affect Body Weight? We eat more (and more) Increased availability of food-service establishments, access to large variety of foods, larger portions encourage people to eat more We sit more and move less Americans eating about 300 calories/day more than in 1985 Labor-saving devices at work and home, sedentary leisure activities (“screen time”) result in decreased energy expenditure 27

5. How Can You Lose Weight Healthfully? National Institutes of Health: overweight individuals should aim to lose about 10 percent of body weight over 6-month period Example: 180-pound person should lose 18 lbs/6 months = 3 lbs/month, ¾ lb/week To lose 1 pound of body fat, need 3,500 calorie deficit Weight loss of ½ to 1 lb/week, need to decrease daily calories by 250 to 500 calories STATS ON PERMAMENT WEIGHT LOSS 28

5. Three Pieces of the Long-Term Weight Loss Puzzle Figure 10.8 29

5. How Can You Lose Weight Healthfully? Successful long-term weight loss requires changes in three areas: diet, physical activity, and behavior Eat smart, because calories count: add satiation to low- calorie meals by including higher-volume foods Eat more vegetables, fruit, and fiber Include some protein and fat in your meals Protein increases satiety most Fat slows movement of food from stomach into intestines Choose lean meat, skinless chicken, fish, nuts, and unsaturated oils. 30

5. Adding Volume to Your Meals Figure 10.9

5. Table 10.3 32

5. The Volume of Food You Eat Figure 10.10 33

5. Exercise! Table 10.4 34

5. Food Log Figure 10.11 35

5. Fad Diets Are the Latest Fad Research shows that reduction of calories, not the composition of the diet, is effective in weight loss. People who adhere the longest to weight-loss diets lose the most weight. High drop-out rates for most extreme diets (Atkins and Ornish diets) Beware of fad diet sensational claims and hype: “It’s the carbs, not calories, that make you fat!” Celebrity-endorsed miracle weight-loss products “Natural” substances help lose weight without risk 36

6. Misc 10.8 37

6. Extreme Measures for Extreme Obesity BMI > 40 = extreme obesity High risk of heart disease, stroke, dying Requires aggressive weight-loss treatment, including very-low-calorie diets, medications, and/or surgery Very-low-calorie diets (< 800 calories) are short-term and must be medically supervised. Medications such as Orlistat can’t replace a lower calorie diet, physical activity, and behavior modification. 38

6. Extreme Measures for Extreme Obesity Gastric bypass and gastric banding result in higher levels of satiety and lower levels of hunger Results in dramatic weight loss and reduction of hypertension, diabetes, high blood cholesterol, and sleep apnea Risks include ulcers, gallstone, bleeding in stomach and intestines Liposuction is performed for cosmetic reasons Fat may reappear, results not permanent Complications such as infections, scars, swelling 39

6. Gastric Bypass and Gastric Binding Misc 10.12 40

7. Table 10.5 41