1. Body Composition
Chapter 6

2. What is Body Composition?
Body composition = the body’s relative amounts of fat mass and fat-free mass (bone, water, muscle, connective and organ tissues, teeth)
Essential fat = crucial for normal body functioning
3–5% of total body weight in males
8–12% of total body weight in females
Nonessential fat = adipose tissue

3. Typical Body Composition
Figure 6.1

4. Overweight and Obesity
The most important consideration in evaluating body weight and composition is the proportion of total body weight that is fat (percent body fat)
Overweight = total body weight above a recommended range for good health
Obesity = severely overweight and overfat; characterized by excessive accumulation of body fat

5. Adult Obesity in California (2008)
Figure 6.2

6. Obesity Trends Among U.S. Adults 1990
No Data <10% %–14%
Source: Behavioral Risk Factor Surveillance System, CDC

7. Obesity Trends* Among U.S. Adults 2009
Source: Behavioral Risk Factor Surveillance System, CDC
No Data <10% %–14% %–19% %–24% ≥25%
No Data <10% %–14% %–19% %–24% ≥25%

8. Excess Body Fat and Wellness
Increased risk of chronic disease and premature death; associated health problems include:
Unhealthy blood fat levels
Impaired heart function
Heart disease and hypertension
Cancer
Impaired immune function
Gallbladder disease
Kidney disease
Skin problems
Sleeping problems

9. Obesity and Exercise
Activity improves health for people who are normal weight, overweight, and obese.
p. 179

10. Body Composition and Diabetes
Obese people are more than three times as likely as non-obese people to develop diabetes
Excess body fat is a key risk factor for the most common type of diabetes

11. Diabetes Diabetes mellitus = disruption of normal glucose metabolism
Type 1 diabetes = the pancreas produces little or no insulin
Type 2 diabetes = the pancreas doesn’t produce enough insulin, cells are resistant to insulin, or both
Gestational diabetes = develops in 2–5% of pregnant women
Pre-diabetes = elevated blood glucose levels

12. Diabetes
< 100

13. Diabetes: Prevalence
Source: National Center for Health Statistics

14. Diabetes: Symptoms

15. Diabetes: Prevention
Regular physical activity including endurance exercise and weight training
Moderate diet rich in whole grains, fruits, vegetables, legumes, fish, and poultry
Modest weight loss
For people with pre-diabetes, lifestyle changes are more effective than medication in preventing diabetes

16. Diabetes: Treatment
Keep blood sugar levels within safe limits through diet, exercise, and, if needed, medication
Monitor blood sugar levels with a home test
Lose weight if overweight

17. Diabetes: Treatment
Source: Royalty-free/Corbis (courtesy of McGraw-Hill Higher Education)

18. Body Fat Distribution and Chronic Disease
Location of fat is important to health
People who gain weight in the abdominal area = “apples;” this group has an increased risk of coronary heart disease, high blood pressure, diabetes, and stroke
People who gain weight in the hip area= “pears”

19. Body Composition and Wellness
Excess body fat decreases the ability to perform physical activities
Unrealistic expectations about body composition can hurt self-image; exercise improves body image
Set a realistic goal and maintain a wellness lifestyle to develop a healthy body composition

20. Problems Associated with Very Low Levels of Body Fat
Too little body fat is associated with reproductive, circulatory, and immune system disorders
Less than 8–12% for women
Less than 3–5% for men

21. Female Athlete Triad
A condition consisting of three interrelated disorders

22. Body Mass Index
A rough assessment based on the concept that a person’s weight should be proportional to height
Body weight in kilograms is divided by the square of height in meters
Elevated BMI is linked to increased risk of disease, especially if associated with large waist circumference

23. Calculating BMI
BMI is relatively easy and inexpensive to measure and calculate using the following formulas:
BMI = Weight (kg)/Height2 (m) or
BMI = Weight (lb) x 703/Height (inches)/Height (inches)
Rather than calculating BMI, the table presented on the following slide can be used as a quick reference.
ACE also provides valuable fitness calculators and assessment support materials on its website.

25. Body Mass Index

26. Body Mass Index and Risk of Type 2 Diabetes
Figure 6.3

27. Estimating Percent Body Fat
Underwater weighing: An individual is submerged and weighed under water. Percentages of fat and fat-free weight are calculated from body density.
The Bod Pod: The amount of air displaced by a person in a small chamber is measured by computerized sensors.

28. Estimating Percent Body Fat
Bioelectrical impedance analysis (BIA): A small electrical current is sent through the body, and the resistance of the body to it is recorded. The resulting estimates of how much water is in the body can be used to determine body composition.
Dual energy X-ray absorptiometry (DEXA) measures the tissue absorption of high- and low-energy X-ray beams.
Total body electrical conductivity (TOBEC) estimates lean body mass by passing the body through a magnetic field.

29. Bioelectrical Impedance Analysis
Simpler to administer, but accuracy is questionable
Sensors are applied to the skin and a weak electrical current is run through the body to estimate body fat, lean body mass, and body water
Based on the principle that fatty tissue is a less-efficient conductor of an electrical current

30. DEXA Dual energy X-ray absorptiometry (DEXA)
Frequently used by research and medical facilities
Considered by many as the standard technique for body composition assessment
Uses low-dose beams of X-ray energy
Measures fat mass, fat distribution pattern, and bone density
Procedure is simple; takes only 15 minutes to administer
Not readily available to most fitness participants

31. Magnetic Resonance Imaging (MRI)
Computed Tomography (CT)
Total body electrical conductivity (TOBEC)

32. Setting Body Composition Goals
If fat loss would benefit your health, set a realistic goal in terms of percent body fat or BMI
If you have underlying health issues, check with your physician before setting a goal
A little weight loss at a time can be very beneficial; focus on a healthy lifestyle including proper diet and exercise

33. Making Changes in Body Composition
Lifestyle should focus on:
Regular physical activity, endurance exercise, and strength training
Figure 6.4

34. Assessing Body Fat Distribution
Disease risk increases with total waist measurement of more than
40 inches for men
35 inches for women
Disease risk increases with total waist-to-hip measurement above
0.94 for young men
0.82 for young women
Image source: Jupiter Images (courtesy of McGraw-Hill Higher Education)

35. Estimating Percent Body Fat
Skinfold measurements: Folds of skin are measured with a caliper. The measurements are used in equations that link the thickness of skinfolds to percent body fat calculations made from more precise experiments.

36. Jackson and Pollock Three-site Skinfold for Men
Chest
A diagonal skinfold taken midway between the anterior axillary line and the nipple
Thigh
A vertical skinfold taken on the anterior midline of the thigh between the inguinal crease and the proximal border of the patella
Abdomen
A vertical skinfold taken 2 cm (~1 inch) to the right of the umbilicus

37. Jackson and Pollock Three-site Skinfold for Women
Triceps
A vertical fold on the posterior midline of the upper arm taken halfway between the acromion and olecranon processes
Thigh
A vertical skinfold taken on the anterior midline of the thigh between the inguinal crease and the proximal border of the patella
Suprailium
A diagonal fold following the natural line of the iliac crest taken immediately superior to the crest of the ilium and in line with the anterior axillary line

38. Skinfold Technique: Percent Fat Estimates for Women

39. Skinfold Technique: Percent Fat Estimates for Men under 40

40. Sample Desired Body Weight Calculation
Desired body weight = [Lean body weight / (100% – Desired % fat)] x 100
Starting information:
Female client’s current weight is 168 pounds, with 28% body fat
Initial goal: To achieve 24% body fat without losing lean tissue
Determine fat weight in pounds:
Body weight x Body-fat percentage (BF%): 168 lb x 28% = 47 lb of fat
Determine lean body weight (LBW):
Total weight – Fat weight: 168 lb – 47 lb = 121 lb of lean tissue
Calculate %LBW at desired %Fat:
Desired %LBW at 24% body fat = 100% – 24% = 76% (or 0.76)
Calculate goal weight:
Divide current LBW by desired %LBW = 121 lb/0.76 = 159 lb

41. Making Changes in Body Composition
Lifestyle should focus on:
Moderate energy intake
Physical activity is the key to long-term success
Source: Steve Cole/Getty Images (courtesy of McGraw-Hill Higher Education)

42. Chapter 6 Connect Worksheet
Chapter 6 Connect Worksheet is due on Monday, October 15th, no later than 11:59PM.