Causes of Obesity Genetics: Influences eating behavior Impacts body composition Affects risk of obesity Two to three times higher with family history of obesity Interrelated with environment factors

Causes of Obesity (cont’d.) Research involving proteins Lipoprotein lipase (LPL) enzyme: higher level of activity in fat cells of obese people Obesity (ob) gene: codes for the protein leptin What is the role of leptin, and what is leptin resistance? Ghrelin: stimulates appetite and promotes efficient energy storage

Causes of Obesity (cont’d.) Fat cells in obese people compared to healthy-weight people Higher number Larger fat cells What happens to the number and size of fat cells with weight loss? Set-point theory Body weight: physiologically regulated

Figure 7-1 Fat Cell Development Fat cells are capable of increasing their size by 20-fold and their number by several thousandfold.

Causes of Obesity (cont’d.) Environment Readily available high-kcalorie foods Large serving sizes Energy dense foods Psychological stimuli What is the difference between hunger and appetite? Food behavior: linked to emotional needs

Causes of Obesity (cont’d.) Physical inactivity Sedentary screen time Technology Physical activity displaced at home, at work, at school, and in transportation Obstacles to physical activity and healthy foods Aspects of the built environment What are food deserts?

Causes of Obesity (cont’d.) National Academies’ Institute of Medicine National goals to counter obesity and improve the nation’s health Make physical activity an integral and routine part of American life Make healthy foods and beverages available Advertise and market what matters for a healthy life Activate employers and health-care professionals Strengthen schools as the heart of health

Obesity Treatment: Who Should Lose? Factors Extent of overweight, age, health, genetics, etc. Must weigh the benefits and risks of weight loss

Inappropriate Obesity Treatments Over-the-counter (OTC) weight-loss products Weight loss pills, powders, and other dietary supplements Other gimmicks Steam and sauna baths Brushes, sponges, wraps, creams, and messages

Aggressive Treatments of Obesity Obesity drugs Beneficial with modest weight loss As part of a long-term, comprehensive weight-loss program Must consider risks of long-term use FDA-approved drugs for weight loss (Table 7-1)

Aggressive Treatments of Obesity (cont’d.) Surgery Most effective treatment for clinically severe obesity (morbid obesity) Types of procedures Gastric bypass Gastric banding Laparoscopic weight-loss surgery Significant, long-term weight loss; shortens recovery; and less invasive than open surgery

Reasonable Strategies for Weight Loss Must integrate Healthy eating patterns, physical activities, supportive environments, and psychosocial support Successful strategies Embrace small changes, moderate losses, and reasonable goals

Reasonable Strategies for Weight Loss (cont’d.) Dietary Guidelines for Americans for weight loss Consume fewer kcalories from foods and beverages Increase physical activity Reduce time spent in sedentary behaviors

Reasonable Strategies for Weight Loss (cont’d.) Reasonable goals to reduce weight to lower disease risk Reduce body weight by about 10 percent over half a year’s time Maintain a lower body weight over the long term At a minimum, prevent further weight gain

Reasonable Strategies for Weight Loss (cont’d.) A healthful eating plan Energy intake Provides less energy than the person needs to maintain present body weight Not too restrictive Eating pattern for safely losing weight Men: 1600 kcalories per day Women: 1200 kcalories per day

Table 7-2 Daily Amounts from Each Food Group for 1200- to 1600-kCalorie Diets

Reasonable Strategies for Weight Loss (cont’d.) A healthful eating plan Breakfast is important Frequency is inversely associated with obesity Results in higher overall diet quality and lower daily energy density Maintain nutritional adequacy Consume a minimum of 1200 kcal per day

Reasonable Strategies for Weight Loss (cont’d.) A healthful eating plan Food selections Fresh fruits and vegetables; low-fat milk products or substitutes; legumes; small amounts of lean meats, seafood, poultry, or meat alternatives; nuts; whole grains; and enough unsaturated oils to support health Dietary supplement Vitamins and minerals at or below 100 percent of the Daily Values

Reasonable Strategies for Weight Loss (cont’d.) A healthful eating plan Small portions Foods with lower energy density Fruits, vegetables, and broth-based soups Limited intakes of added sugars and alcohol Small, frequent meals Adequate water

Figure 7-2 Energy Density Selecting grapes with their high water content instead of raisins increases the volume and cuts the energy intake in half. Even at the same weight and similar serving sizes, the fiber-rich broccoli delivers twice the fiber of the potatoes for about one-fourth the energy. By selecting the water-packed tuna (on the right) instead of the oil-packed tuna, a person can enjoy the same amount for fewer kcalories. Decreasing the energy density (kcal/g) of foods allows a person to eat satisfying portions while still reducing energy intake. To lower energy density, select foods high in water or fiber and low in fat.

Reasonable Strategies for Weight Loss (cont’d.) Physical activity Combined with energy restriction More likely to lose more fat, retain more muscle, and regain less weight than diet alone Physical Activity Guidelines for Americans, 2008 (Table 1-5 – Chapter 1) Benefits Reduces abdominal obesity, improves blood pressure, insulin resistance, etc.

Table 7-3 Physical Activity Strategies for Weight Management

Reasonable Strategies for Weight Loss (cont’d.) Physical activity Directly increases energy output Energy spent on various activities (Table 6-2 – Chapter 6) BMR Elevated following physical activity Rises as more lean tissue is added Appetite control

Reasonable Strategies for Weight Loss (cont’d.) Physical activity Psychological benefits Curbs emotional eating Reduces stress Improves self-esteem What kind of physical activity is best for health?

Reasonable Strategies for Weight Loss (cont’d.) Behavior and attitude Behavior modification Manipulating antecedents, the behavior itself, and consequences Behavior awareness: keep a diary Technology tools for tracking daily food and physical activity Applications for smart phones Social media sites

Figure 7-3 Food and Activity Diary The entries in a food and activity diary should include the times and places of meals and snacks, the types and amounts of foods eaten, and a description of the individual’s feelings when eating. The diary should also record physical activities: the kind, the intensity level, the duration, and the person’s feelings about them.

Reasonable Strategies for Weight Loss (cont’d.) Behavior and attitude Focus on desired behaviors and eliminating unwanted behaviors Set small time-specific goals “How To” apply behavior modification to manage body fatness Cognitive skills: “positive self-talk”

Reasonable Strategies for Weight Loss (cont’d.) Behavior and attitude Identify stressors Learn to practice problem-solving skills Weight maintenance Long-term success behaviors Believe in ability to control weight (self-efficacy), eat breakfast, stay physically active, monitor weight once per week, maintain lower-kcalorie eating patterns, etc.

Table 7-4 Weight-Loss Strategies

Strategies for Weight Gain Underweight Affects about two percent of U.S. adults Physical activity Focus on resistance training with increased energy intake Energy-dense foods Choose high-kcalorie items from each food group

Strategies for Weight Gain (cont’d.) Consume at least three healthy meals daily Large portions at each meal Have extra snacks between meals Increase kcalories with beverages Juice and milk

Table 7-5 Weight-Gain Strategies