Understanding Body Composition

Learning Outcomes Discuss how body composition is related to lifelong fitness and wellness. Describe how the assessment of body size and shape differs from the assessment of body composition. Evaluate your BMI and body circumferences and relate your scores to your overall health status. Set and continually reevaluate goals to reach your healthy body fat percentage. © 2013 Pearson Education, Inc.

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 © 2013 Pearson Education, Inc.

Body Composition Concepts continued 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 © 2013 Pearson Education, Inc.

Body Composition for Men and Women © 2013 Pearson Education, Inc.

Why Do My 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. © 2013 Pearson Education, Inc.

How Can I Evaluate My Body Size and Shape? Calculate your body mass index (BMI). BMI: a common measurement to assess disease risks Understand the limits of BMI: Scores do not differentiate between fat and lean body mass. Measure your body circumference: Use waist and hip measurements to determine your waist-to-hip ratio (WHR). © 2013 Pearson Education, Inc.

Estimating BMI © 2013 Pearson Education, Inc.

BMI and Health © 2013 Pearson Education, Inc.

Waist Circumference, BMI, and Disease Risk © 2013 Pearson Education, Inc.

How to Evaluate Body Size and Shape continued Identify your body's patterns of fat distribution. Gynoid Pattern "Apple" shaped Excess body fat on upper body and trunk Associated with greater disease risk Android Pattern "Pear" shaped Excess fat mainly on lower body (hips and thighs) © 2013 Pearson Education, Inc.

Android and Gynoid Body Fat Distribution © 2013 Pearson Education, Inc.

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 © 2013 Pearson Education, Inc.

Assessing Body Composition continued 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 © 2013 Pearson Education, Inc.

A DXA Machine Uses Low-Radiation X-rays to Determine Body Composition © 2013 Pearson Education, Inc.

Hydrostatic Weighing Uses Total Body Water Displacement to Calculate Estimated Body Fat © 2013 Pearson Education, Inc.

The "Bod Pod" Uses Total Body Air Displacement to Calculate Body Fat © 2013 Pearson Education, Inc.

Bioelectrical Impedance Analysis (BIA) Measures Resistance of Tissues to Electrical Currents © 2013 Pearson Education, Inc.

How Can I Evaluate and Change My Body Composition? Determine if your percent body fat is within a healthy range. Set reasonable composition goals. Follow a well-designed exercise and nutrition plan. Regularly monitor your body size, shape, and composition. © 2013 Pearson Education, Inc.

Percent Body Fat Norms for Men and Women © 2013 Pearson Education, Inc.

How can a person who is "normal" weight be at risk for obesity-related diseases? What are health risks of women who are normal-weight obese? In addition to increased percentage of body fat, what characteristic of body fat points to increased health risks? Normal Weight Obesity © 2013 Pearson Education, Inc.

Follow a Well-Designed Exercise and Nutrition Plan 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. © 2013 Pearson Education, Inc.