Body Composition © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

Health Risks Associated with Levels of Body Fat © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

Obesity Rates in United States © 2014 Pearson Education, Inc.

Creeping Obesity © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

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) © 2014 Pearson Education, Inc.

Skinfold Test Exercise Video: Skinfold Test PLAY © 2014 Pearson Education, Inc.

Waist-to-Hip Measurement PLAY Exercise Video: Waist-to-Hip Measurement © 2014 Pearson Education, Inc.

Estimating BMI © 2014 Pearson Education, Inc.

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 = 129.5 lb fat-free weight Step 2. Calculate optimal weight Optimal weight = fat-free weight/(1 – optimal % fat) 129.5/(1 – .08) = 140.8 lb optimal weight 129.5/(1 – .19) = 159.9 lb optimal weight See Lab 6.2 worksheet to determine ideal body weight © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.

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 © 2014 Pearson Education, Inc.