1. 7: Body Weight and Body Composition
Your Health Today, 6th edition

2. Overweight and Obesity
Overweight: body weight that exceeds the recommended guidelines for good health
Obesity: body weight that greatly exceeds the recommended guidelines
No sex, age, state, racial group, or educational level is spared from these problems, although they are worse for the young and the poor
Overweight and obesity are associated with serious health problems

3. What Is a Healthy Body Weight?
There is no ideal body weight for each person, but there are ranges for a healthy body weight
A healthy body weight is defined as:
Acceptable Body Mass Index (BMI)
Body composition with an acceptable amount of body fat
Fat distribution that is not a risk factor for illness
Absence of any medical conditions that would suggest the need for weight loss

4. Body Mass Index
Body mass index (BMI) is a measure of body weight in relation to height
See Table 7.1
There appears to be a U-shaped relationship between BMI and risk of death, with the lowest risk in the 18.5 to 25 range
Underweight: BMI less than 18.5
Healthy weight: BMI between 18.5 and 24.9
Overweight: BMI between 25 and 29.9
Obese: BMI of 30 or greater

5. Body Mass Index (2) BMI may incorrectly estimate risk for some people
For those with muscular build, BMI may overestimate body fat
For the elderly or others with low muscle mass, BMI may underestimate body fat

6. Body Fat Percentage
Different groups have different body fat expectations
Healthy range for a typical male is 8–24%; male athletes, 5–10%
Healthy range for a typical female is 21–35%; female athletes, 15–20%
Below a certain body fat threshold, hormones cannot be produced and health problems can occur
Body fat percentage can be measured by:
Immersion (most accurate), X-ray, skinfold measurement, and bioelectrical impedance

7. Body Fat Distribution
Where you carry your body fat is important in determining your health risk
A large abdominal circumference is associated with high cholesterol levels and higher risk for heart disease, stroke, diabetes, and hypertension
Obese men tend to accumulate abdominal fat
Obese women tend to accumulate hip and thigh fat; however, the onset of menopause shifts weight gain to the abdomen
If your BMI is in the healthy range, a large waist may signify an independent risk for disease

8. Issues Related to Overweight and Obesity
Obese people are four times more likely to die before their expected lifespan and have increased risk for:
High blood pressure
Diabetes
Elevated cholesterol levels
Coronary heart disease
Stroke
Gallbladder disease
Osteoarthritis
Sleep apnea
Lung problems
Certain cancers, such as uterine, prostate, and colorectal

9. Diabetes and Obesity
The rates of obesity and diabetes in the U.S. have risen in parallel
About 90–95% of people with diabetes have Type-2, the form strongly associated with obesity
About 80% of American youth with Type-2 diabetes are obese
At any age group, small reductions in weight through diet and exercise reduce the risk of developing diabetes

10. Discrimination and Obesity
Overweight children are often teased or bullied
Weight-related bullying does not stop with adulthood
The overweight face discrimination in hiring practices, lower wages, and social stigma
A study found the overall, tangible cost of obesity for a woman was $4,879 per year, and for a man, $2,646

11. The Problem of Underweight
A sudden, unintentional weight loss without a change in diet or exercise level may signify an underlying illness and should prompt a visit to a physician
If you have difficulty keeping weight on, to gain weight you need to change your energy balance
Eat more frequent and energy-dense meals
Add nutritional supplements as snacks
Reduce aerobic exercise and increase resistance or weight training

12. What Factors Influence Your Weight?
Many factors contribute to this trend, both individual and environmental
For most people, obesity is a multifactorial condition: a person’s susceptibility is due to a complex interaction among multiple genes and his or her environment

13. Genetic and Hormonal Influences
Your risk of becoming obese if both your parents are obese is 80 percent
Hundreds of genes have been associated with BMI and obesity
In most cases, multiple genes may predispose toward obesity, but interactions with the environment determine outcome
Genetic affects on hormone levels result in alterations in appetite or energy expenditure

14. Genetic and Hormonal Influences (2)
Stress response also affects eating patterns
The body releases several hormones, and in response, fat cells release fatty acids and triglycerides and increase circulating glucose
When stress is chronic, the constant presence of these hormones increases the amount of fat deposited in the abdomen
Stress also affects eating patterns

15. Genetic and Hormonal Influences (3)
Thyroid disorders can be associated with weight gain or weight loss
Thyroid gland controls much of your metabolic rate through hormone production
When it is overactive, weight loss will likely result
When it is not active enough, weight gain will likely result

16. Age and Gender
Poor childhood eating habits are believed to be a major cause of the recent surge in overweight and obesity
Healthy body fat percentage changes as we age
Children, 12%
Male adults, 15%; female adults, up to 25%
Between the ages of 20 and 40, both men and women gain weight
Older adults are susceptible to weight gain and need to be attentive to their lifestyle in order to maintain a healthy weight

17. Obesogenic Environments and Lifestyle
Our chances of becoming obese are significantly influenced by our environment
Choice in food is driven by exposure, as well as cost and convenience
In general, unhealthy foods are more convenient and less expensive than healthy foods
Eating out has become a part of daily life
These foods tend to be higher in fat and calories and lower in fiber than a home-cooked meal
When confronted with large serving sizes, people eat more and don’t realize it

18. Obesogenic Environments and Lifestyle (2)
Our car-friendly, pedestrian-unfriendly communities mean people are less likely to walk
Americans spend much of their leisure time on sedentary entertainments like TV and the Internet
Less sleep, not more, is associated with weight gain in young adults
If your friends gain weight, you are more likely to gain weight
Weight cycling—repeated cycles of weight loss and weight gain as a result of dieting—contributes

19. The Key to Weight Control: Energy Balance
Energy balance: the relationship between caloric intake (in the form of food) and caloric output (in the form of metabolism and activity)
If you take in more calories than you use through metabolism and movement (positive energy balance), you store these extra calories as body fat
If you take in fewer calories than you need (negative energy balance), you draw on body fat stores to provide energy

20. Estimating Your Daily Energy Requirements
You can estimate your daily energy expenditure by considering the:
Thermic effect of food
Energy spent on basal metabolic rate, and
Energy spent on physical activities

21. Estimating Your Daily Energy Requirements (2)
Thermic effect of food: an estimate of the energy required to process the food
Estimated at 10% of energy intake
Basal metabolic rate (BMR): rate at which the body uses energy to maintain basic life functions, such as digestion, respiration, and temperature regulation
About 60–70% of energy consumed
Between 10% and 30% of the calories consumed each day are used for physical activity

22. Adjusting Your Caloric Intake
Reasonable weight loss of 1 pound to 2 pounds per week is a healthy goal
A pound of body fat stores 3,500 calories
To lose 1 pound in a week, you need to decrease your total intake for the week by that 3,500 calories
Faster weight loss tends to include loss of lean tissue and a decrease in your basal metabolic rate
Foods high in complex carbohydrates have a greater thermic effect and take more energy to process than high-fat foods

23. Fad Diets
Popular fad diets promote rapid change but are not associated with long-term weight loss
Most follow a pattern of altering the balance of carbohydrates, protein, and fat
Many label certain foods as “good” or “bad” or prescribe certain “fat-burning foods”
Most dietitians and physicians encourage more balanced options and self-monitoring concepts

24. Weight Management Organizations
Weight management organizations offer group support, nutrition education, dietary advice, exercise counseling, and other services
Weight Watchers: a commercial program
Take Off Pounds Sensibly (TOPS): a free program providing group support; focuses on teaching
Overeaters Anonymous: a free program providing group support; more suitable for binge eaters or others with emotional issues related to weight

25. The Medical Approach Very-low-calorie diets Prescription drugs
An aggressive option that requires a physician’s supervision
Maintaining weigh loss is challenging
Prescription drugs
Two types: those that act in brain to reduce food intake and those that act elsewhere in the body to reduce food absorption
Side effects are an issue

26. The Medical Approach (2)
Surgical options
Gastric surgery is never a first-line approach
Typical weight loss ranges from 20% to 30% of weight
Nonprescription diet drugs and dietary supplements
Diet teas, bulking products, starch blockers, diet candies, sugar blockers, benzocaine, etc.
There are many safety concerns
Manufacturers of dietary supplements do not have to submit proof of their efficacy or safety to the FDA

27. The Size Acceptance Movement
Seeks to decrease negative body image, encourage self-acceptance, and end discrimination
Emphasizes that people of any size can become more fit and benefit from healthier food choices
The goal is to find a balanced approach that combines personal acceptance with promotion of a healthy body composition

28. Tasks for Individuals Emphasize components of a healthier lifestyle
A balanced diet emphasizing fruits, vegetables, and whole grains in appropriate portion sizes
150 minutes weekly of moderate-intensity physical activity
Reduced time spent in sedentary activities
Target improvement in areas such as blood pressure, cholesterol, and blood sugar level
Inclusion of peer support
Self-acceptance of body size
Follow-up evaluation by a health professional

29. Tasks for Individuals (2)
Set SMART goals
SMART: Specific, Measurable, Attainable, Realistic, Timely
Is the goal specific?
Is the goal measurable?
Is the goal attainable, through action on your part?
Is the goal realistic, using small, gradual changes?
Is the goal timely, in that you set a time line for when you will reach it?

30. Tasks for Individuals (3)
Choose an appropriate diet approach, based on specific goals
Lose or gain a small amount of weight
Maintain weight loss long-term
Replace unhealthy eating and exercise behaviors with more healthy behaviors
Reduce risk or controlling symptoms of diabetes (including maintainable short-term weight loss)
Improve heart health

31. Table 7.2 Dieting Approaches
Type
Theory
Examples
Balanced diets (for diabetes and heart heath as well as weight loss)
Encourage some restriction of total calorie intake and focus on lower carbohydrates and lower fats. They tend toward balance among food groups.
DASH, Dr. Weil’s Anti-inflammatory, flexitarian, Jenny Craig, Mediterranean, Mayo Clinic, traditional Asian, Volumetrics, Weight Watchers, Zone
Commercial diet programs
Typically based on changing food patterns and increasing exercise, with the help of behavioral counseling and support systems.
Jenny Craig, Nutrisystem, Weight Watchers
Low-calorie diets (includes most weight-management organizations)
Specifically incorporate reduction in overall calorie intake.
Body Reset, HMR, Jenny Craig, Nutrisystem, raw food, Weight Watchers

32. Table 7.2 Dieting Approaches (Continued)
Type
Theory
Examples
Food-group-restrictive diets
Certain types of food classified as “bad” are eliminated; other foods are “good” metabolic promoters.
Low-fat: macrobiotic, Ornish, TLC, vegetarian, vegan. Low-carb/high-protein: Atkins, Paleo, South Beach. Detox: Master Cleans (aka Lemonade Diet)
Meal replacements (shakes and bars)
Prepacked bars and drinks are used to control calorie intake.
Body Reset, HMR, Medifast, Slim-Fast
Prepackaged meals
Purchased meals are used to control calorie intake.
HMR, Jenny Craig, Nutrisystem, Weight Watchers

33. Tasks for Individuals (4)
Evaluate the support and obstacles in your environment, asking yourself if your change in diet is:
Realistic
Moderate and flexible
Safe
Holistic, incorporating regular exercise
Compatible with your relationships
Affordable
Research-based

34. Tasks for Individuals (5)
Use tools to help change your patterns
Stimulus control: identify environmental cues associated with unhealthy eating habits
Self-supervision: keep a log of the food you eat and the physical activity you do
Social support and positive reinforcement: recruit others to join you in your healthier habits
Stress management: use healthy techniques and problem-solving strategies to handle stress
Cognitive restructuring: moderate any self-defeating thoughts and emotions; redefine your body image by thinking about what your body can do

35. Tasks for Society
Changes in social policies are also needed to combat the obesity epidemic
Promote healthy foods, lowering the price of low-fat, nutritious food to increase the rates at which people choose them
Support active lifestyles through community planning
Support consumer awareness
If consumers don’t buy the products depicted in ads, or if they complain about the content of ads, food manufacturers will eventually respond
Encourage health insurers to cover obesity prevention programs

36. In Review How is healthy body weight defined?
What factors influence weight?
What is the best way to manage body weight?
Are there quick fixes for overweight and obesity?
How can individuals and society promote healthy weight throughout life?