1. Body Composition
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2. Learning Objectives Define body composition
Explain the relationship between body fat percentage and disease risk
Explain the concept of optimal body weight
Discuss the importance of assessing body composition
Explain body composition assessment using hydrostatic weighing, the skinfold test, body mass index, and waist-to-hip circumference ratio
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3. Body Composition
The relative amounts of fat and fat-free tissues (bone, muscle, organs) in the body
Expressed as percentage of fat in the body
Overweight
body fat percentage above the recommended level
Obesity
>25% body fat for men
>35% body fat for women
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4. Body Composition Relationship to Health
Essential Fat
Located in nerves and cell membranes
Necessary for body functioning
3% for men
12% for women
Storage Fat
Located in adipose tissue
visceral (around organs)
subcutaneous (below the skin)
8–19% for men, recommended low end of 12–15% for young adult
21–32% for women, recommended low end of 21–25% for young adult
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5. Body Composition Relationship to Health
Android Pattern of Obesity
Fat is primarily stored in upper body and around the waist
Most common in men
Greater risk of developing heart disease and diabetes
Gynoid Pattern of Obesity
Fat is primarily stored in waist, hips, and thighs
Most common in women
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6. Health Risks Associated with Levels of Body Fat
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7. Overweight and Obesity in the United States
Current obesity estimates
34% of adults
17% of children/adolescents ( 2–19 yrs.)
NIH estimates obesity directly contributes to 15–20% of deaths in United States
Contributes significant effect on health care costs
10% of all medical costs in United States
$147 billion per year direct medical costs
predicted to rise sharply in future
WHO indicates U.S. obesity rates highest in world
in 2010 every state had 20% or higher obesity rate
36 states 25% or more
12 states 30% or more
Adult rates are leveling off
Childhood obesity rates show NO evidence of decreasing
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8. Obesity Rates in United States
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9. Creeping Obesity
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10. Chronic Conditions of Overweight and Obesity
Heart disease (also called cardiovascular disease or CVD)
Diabetes
Cancers (breast, prostate, colon)
Joint problems and osteoarthritis
Sleep apnea
Gallbladder disease
Menstrual abnormalities
Difficulty with conception and pregnancy complications
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11. Benefits of a Healthy Weight
Mental Benefits
Better self-esteem & body image
More positive mindset
Less anxiety and depression
Physical Benefits
Lower risk of diabetes, cardiovascular disease, and cancer
Easier motion for physical activity and everyday living
Lower death rate
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12. Health Effects of Underweight
Loss of muscle mass and strength resulting from malnutrition
Osteoporosis
Menstrual abnormalities that can lead to infertility
Severe underweight from eating disorders (anorexia nervosa and bulimia) can lead to
Heart problems
Digestive disorders
Kidney damage
Anemia
Lethargy
Muscle weakness
Dry skin
Compromised immune function
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13. Assessing Body Composition
Field Methods
Height/weight tables
Body mass index (BMI)
Skinfold test
Waist measurement & waist-to-hip ratio
Laboratory Measures
Dual energy X-ray absorptiometry (DXA)
Hydrostatic weighing
Air displacement
Bioelectrical impedance analysis (BIA)
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14. Skinfold Test Exercise Video: Skinfold Test PLAY
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15. Waist-to-Hip Measurement
PLAY
Exercise Video: Waist-to-Hip Measurement
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16. Estimating BMI
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17. Determining Ideal Body Weight
Calculate % body fat and select a healthy body fat % range based on sex and age
Example: Male – age 25, weight 185 lb, 30% body fat, body fat % range of 8–19% recommended
Step 1. Compute fat-free weight
Total body weight – fat weight = fat-free weight
100% – 30% body fat = 70% fat-free weight
70% x 185 lb = lb fat-free weight
Step 2. Calculate optimal weight
Optimal weight = fat-free weight/(1 – optimal % fat)
129.5/(1 – .08) = lb optimal weight
129.5/(1 – .19) = lb optimal weight
See Lab 6.2 worksheet to determine ideal body weight
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18. Weight Management Set goals Get regular body fat assessments
Re-evaluate optimum weight over time
Guard against lean mass loss during weight loss
Incorporate regular aerobic and resistance exercise
Eat a healthy diet
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19. Summary
Body composition is the relative amounts of fat and fat free tissue in the body
A high percentage of body fat is associated with increased risk for numerous diseases
Body fat distribution also affects disease risks associated with overweight and obesity
Common field techniques for estimating body fat include skinfold measurements, BMI assessment, and waist-to-hip ratio
DXA is considered the gold standard measure for estimating body fat
Get regular body composition assessments while trying to lose or gain weight
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