Objectives Define body composition. Explain why the assessment of body size, shape, and composition is useful. Explain how to perform assessments of body size, shape, and composition. Evaluate your personal body weight, size, shape, and composition. Set goals for a healthy body fat percentage. Plan for regular monitoring of your body weight, size, shape, and composition.

Body Composition Concepts The relative amounts of lean tissue and fat tissue in your body. Lean Body Mass Your body’s total amount of lean/fat-free tissue (muscles, bones, skin, organs, body fluids). Fat Mass Body mass made up of fat tissue.

Body Composition Concepts Percent Body Fat The percentage of your total weight that is fat tissue (weight of fat divided by total body weight). Essential Fat Fat necessary for normal body functioning (including in the brain, muscles, nerves, lungs, heart, and digestive and reproductive systems). Storage Fat Nonessential fat stored in tissue near the body’s surface.

Why Body Size, Shape, and Composition Matter Knowing body composition can help assess health risks. More people are now overweight or obese. Estimates of body composition provide useful information for determining disease risks. Evaluating body size and shape can motivate healthy behavior change. Changes in body size and shape can be more useful measures of progress than body weight. Overweight vs. Overfat

Body Composition for Men and Women For typical 20-24 year old men and women

How to Evaluate Body Size and Shape Calculate your body mass index (BMI) using your height and weight. BMI: A common measurement to assess disease risks. Understand the limits of BMI: Scores do not differentiate between fat and lean body mass – limited benefit for individuals. Good for large populations used in research

Estimating BMI

BMI and Health

Health Risks Associated with Body Size and Shape Measure your body circumference: Use waist and hip measurements to determine your waist-to-hip ratio (WHR). (Lab 7.2) Android Pattern “Apple” shaped Excess body fat on upper body and trunk Associated with greater disease risk Gynoid Pattern “Pear” shaped Excess fat mainly on lower body (hips and thighs) Increased risk for a waist size larger than 40 inches for men and 35 inches for women. A higher WHR is associated with more health risks.

Android and Gynoid Body Fat Distribution

Assessing Body Composition Skinfold Measurements Use calipers to measure skinfold thickness. Accurate assessments require experience and practice. Dual-Energy X-Ray Absorptiometry (DXA) The “gold standard” for assessing body composition. Uses low-radiation x-rays to distinguish body components. Hydrostatic Weighing (Underwater Weighing) Requires an equipped facility. Measures water displacement/buoyancy

Assessing Body Composition Air Displacement (Bod Pod) Measures total body air displacement. Used with other measures for a full assessment. Bioelectrical Impedance Analysis (BIA) Measures resistance of tissues to electrical currents. Accuracy depends on machine quality and participant cooperation. Estimates from Circumferences or BMI Provide rough estimates. Can provide a starting point for weight management.

Bioelectrical Impedance Analysis (BIA)

Evaluating or Changing Your Body Composition Determine if your percent body fat is within a healthy range. Set reasonable goals. Follow a well-designed exercise and nutrition plan. Regularly monitor your body size, shape, and composition.

Men - 8-22% Women - 20-35%

Evaluating or Changing Your Body Composition Weekly Assess your body shape and size (use indicators such as a mirror and the fit of your clothes). Assess your weight. Monthly or Every Few Months Measure your body’s circumferences. Measure your BMI. Measure your percent body fat.