1. Energy Balance, Body Composition, and Weight Management
Chapter 8
Energy Balance, Body Composition, and Weight Management

2. Energy Equilibrium
Energy Intake refers to the amount of fuel (calories) you take in through consumption of carbohydrate, protein, fat and alcohol.
Energy Output is the amount you expend – primarily for basic body functions, physical activity, and the processing of food.
Energy equilibrium is demonstrated in people who maintain a relatively constant weight.

3. Positive Energy Balance
Positive energy balance – when you take in more energy than your body needs.
Surplus is stored as fat (long-term) and glycogen (short-term).
Pregnant women and growing children need a positive energy balance.
A positive energy balance due to overeating and inactivity leads to weight gain.

4. Negative Energy Balance
Negative energy balance – when you take in less energy than your body needs.
Illness.
Intentional change for weight loss.
The body uses stores of glycogen and fat (protein as well with extreme deficits).

5. Energy Equilibrium
Energy equilibrium – when the energy intake is about equal to the energy output.
Body weight change reflects overall energy balance.

6. Energy Balance

7. Bomb Calorimeter
We can measure the energy content of a food with a bomb calorimeter.

8. Bomb Calorimeter
Food is completely burned inside a sealed chamber and sensors measure the amount of heat produced by combustion.
The human body does not completely digest all food and is unable to oxidize nitrogen. Therefore, we adjust the energy content downward to reflect this.

9. Energy In Regulation of intake Hunger Satiation Satiety Appetite
Prompts eating; physiological desire
Satiation
Signals to stop eating
Satiety
Lack of hunger
Appetite
Psychological desire

10. Hunger
The internal, physiological drive to find and consume food. Unlike appetite, hunger is usually experienced as a negative sensation, often manifesting as an uneasy and painful sensation.

11. Appetite
Appetite is a psychological desire to eat that is related to the pleasant sensations often associated with food.
Appetite can trigger a desire for food, even when you are not truly hungry.
Anorexia is a decreased desire to eat food.
Polyphagia (hyperphagia) is an increased desire to eat food.

12. Satiation / Satiety
Satiation is a feeling of satisfaction and fullness that terminates a meal.
Satiety is a feeling of satisfaction or fullness following a meal that quells the desire for food. It delays subsequent intake.

13. Energy In: Regulatory Factors

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, gender
Physical activity
Highly variable
Affected by body size, fitness level,
type of activity
Thermic effect of food (TEF)
Energy to digest, absorb,
metabolize food

15. Measuring Energy Expenditure
Brief history
Direct vs. indirect calorimetry
Doubly labeled water

16. Estimating Energy Expenditure
EER: Estimated Energy Requirement
Predicts total energy expenditure (TEE)
Equations for males and females
Factors for age, weight, height, physical activity

17. Body Composition: Understanding Fatness and Weight
Assessing body weight
Height–weight tables
Body mass index (BMI)
Weight (kg)  height2 (m)
Assessing body fatness
Body fat distribution
Waist circumference

18. Body Mass Index
What are the health risks associated with being overweight?

19. When Energy Balance Goes Awry
Early theories of weight regulation
Fat cell theory
Set point theory
Influences on weight gain and obesity
Heredity and genetic factors
Sociocultural influences
Age and lifestyle factors
Gender and ethnicity
Socioeconomic factors
Psychological factors

20. Weight Management Perception of weight Setting realistic goals
Weight-management lifestyle
Diet and eating habits
Reduce total calories
Reduce fat calories
Increase complex carbohydrates
Improve eating habits
Increase physical activity
Stress management
Self-acceptance

21. Weight Management Weight-management approaches
Self-help books and manuals
Watch for signs of a fad diet
Self-help groups
Commercial programs
Professional counselors
Prescription drugs
OTC drugs and dietary supplements

22. Weight Management
Weight- management approaches
Surgery

23. Underweight Definition Causes Weight-gain strategies
BMI < 18.5 kg/m2
Causes
Illness
Eating disorders
Metabolic factors
Weight-gain strategies
Small, frequent meals
Fluids between meals
High-calorie foods and beverages

24. Healthy Weight Management
Healthy weight management means focusing on metabolic fitness—healthy levels of blood lipids and blood pressure—rather than on achieving a specific weight.
Permanent healthy behaviors are necessary for a long-term weight-management lifestyle.

25. Why Do We Have Hunger Pangs?
When the stomach has been without food for at least three hours, intense stomach contractions begin, sometimes lasting two to three minutes.
Healthy young people have the strongest contractions, due to good muscle tone in the GI tract.
After 12 to 24 hours, contractions of an empty stomach can cause painful hunger pangs.

26. Overweight and Obesity
Worldwide, the number of overweight or obese people has increased markedly in recent years. The rising rates among children are especially disturbing.
At the same time, more people are engaging in weight-control efforts and starting to do so at younger ages.

27. Emotional Factors
Many people use food to cope with stress and negative emotions. Eating can provide a powerful distraction from loneliness, anger, boredom, anxiety, shame, sadness, and inadequacy.
To combat low moods, low energy levels, and low self-esteem, people often turn to the refrigerator. When we use food and eating to cope with our emotions, binge eating or other disturbed eating patterns can develop.

28. Weight Cycling
Weight cycling is a pattern of losing and regaining weight, over and over again. You might expect this behavior to be harmful, perhaps harder on the body than overweight itself.
However, research shows that the potential benefits of weight loss for obese individuals outweigh the potential risks of weight cycling.

29. Balancing Energy Sources
Balancing energy sources and controlling portion sizes can help reduce overall energy consumption. Reducing fat intake is a major step toward lowering calorie intake. Fiber-rich foods provide a feeling of fullness that can help prevent overeating.
When planning a diet, aim for a caloric intake of 20 to 35 percent fat, 10 to 35 percent protein, and 45 to 65 percent carbohydrate.

30. The Built Environment
Our immediate surroundings influence our behaviors, and researchers have begun to link aspects of the built environment with obesity. The built environment, which can be defined as “human formed, developed, or structured areas,” includes buildings, roads, parks, and transportation systems.
People who live in neighborhoods with sidewalks and safe streets are more physically active. But when neighborhoods have low “walkability” or are considered unsafe, BMIs tend to be higher.

31. Meal Replacements
Some people turn to meal replacements— shakes and bars, for example—to help lose weight. Meal replacements are convenient, often contain added vitamins and minerals, and reduce the choices and temptations available at mealtime.
When compared with traditional, reduced-calorie diet programs, people using meal replacements lost slightly more weight and were less likely to stop the program.

32. Weight-Management Strategies
Books, Internet resources, and commercial programs can help some individuals lose weight. However, consumers should always proceed with caution before spending money. Drugs have potential side effects and must be used with caution and medical supervision.
For those who are extremely obese, surgical intervention is an aggressive, last-resort approach to weight management. Liposuction removes fat cells from specific parts of the body but is not considered an effective approach to weight control.

33. ADA Position on Weight Management
It is the position of the American Dietetic Association that successful weight management to improve overall health for adults requires a lifelong commitment to healthful lifestyle behaviors emphasizing sustainable and enjoyable eating practices and daily physical activity.