2What 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 functioning3–5% of total body weight in males8–12% of total body weight in femalesNonessential fat = adipose tissue
4Overweight 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 healthObesity = severely overweight and overfat; characterized by excessive accumulation of body fat
6Obesity Trends Among U.S. Adults 1990 No Data <10% %–14%Source: Behavioral Risk Factor Surveillance System, CDC
7Obesity Trends* Among U.S. Adults 2009 Source: Behavioral Risk Factor Surveillance System, CDCNo Data <10% %–14% %–19% %–24% ≥25%No Data <10% %–14% %–19% %–24% ≥25%
8Excess Body Fat and Wellness Increased risk of chronic disease and premature death; associated health problems include:Unhealthy blood fat levelsImpaired heart functionHeart disease and hypertensionCancerImpaired immune functionGallbladder diseaseKidney diseaseSkin problemsSleeping problems
9Obesity and ExerciseActivity improves health for people who are normal weight, overweight, and obese.p. 179
10Body Composition and Diabetes Obese people are more than three times as likely as non-obese people to develop diabetesExcess body fat is a key risk factor for the most common type of diabetes
11Diabetes Diabetes mellitus = disruption of normal glucose metabolism Type 1 diabetes = the pancreas produces little or no insulinType 2 diabetes = the pancreas doesn’t produce enough insulin, cells are resistant to insulin, or bothGestational diabetes = develops in 2–5% of pregnant womenPre-diabetes = elevated blood glucose levels
15Diabetes: PreventionRegular physical activity including endurance exercise and weight trainingModerate diet rich in whole grains, fruits, vegetables, legumes, fish, and poultryModest weight lossFor people with pre-diabetes, lifestyle changes are more effective than medication in preventing diabetes
16Diabetes: TreatmentKeep blood sugar levels within safe limits through diet, exercise, and, if needed, medicationMonitor blood sugar levels with a home testLose weight if overweight
17Diabetes: TreatmentSource: Royalty-free/Corbis (courtesy of McGraw-Hill Higher Education)
18Body Fat Distribution and Chronic Disease Location of fat is important to healthPeople who gain weight in the abdominal area = “apples;” this group has an increased risk of coronary heart disease, high blood pressure, diabetes, and strokePeople who gain weight in the hip area= “pears”
19Body Composition and Wellness Excess body fat decreases the ability to perform physical activitiesUnrealistic expectations about body composition can hurt self-image; exercise improves body imageSet a realistic goal and maintain a wellness lifestyle to develop a healthy body composition
20Problems Associated with Very Low Levels of Body Fat Too little body fat is associated with reproductive, circulatory, and immune system disordersLess than 8–12% for womenLess than 3–5% for men
21Female Athlete TriadA condition consisting of three interrelated disorders
22Body Mass IndexA rough assessment based on the concept that a person’s weight should be proportional to heightBody weight in kilograms is divided by the square of height in metersElevated BMI is linked to increased risk of disease, especially if associated with large waist circumference
23Calculating BMIBMI is relatively easy and inexpensive to measure and calculate using the following formulas:BMI = Weight (kg)/Height2 (m)orBMI = 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.
26Body Mass Index and Risk of Type 2 Diabetes Figure 6.3
27Estimating 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.
28Estimating 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.
29Bioelectrical Impedance Analysis Simpler to administer, but accuracy is questionableSensors are applied to the skin and a weak electrical current is run through the body to estimate body fat, lean body mass, and body waterBased on the principle that fatty tissue is a less-efficient conductor of an electrical current
30DEXA Dual energy X-ray absorptiometry (DEXA) Frequently used by research and medical facilitiesConsidered by many as the standard technique for body composition assessmentUses low-dose beams of X-ray energyMeasures fat mass, fat distribution pattern, and bone densityProcedure is simple; takes only 15 minutes to administerNot readily available to most fitness participants
32Setting Body Composition Goals If fat loss would benefit your health, set a realistic goal in terms of percent body fat or BMIIf you have underlying health issues, check with your physician before setting a goalA little weight loss at a time can be very beneficial; focus on a healthy lifestyle including proper diet and exercise
33Making Changes in Body Composition Lifestyle should focus on:Regular physical activity, endurance exercise, and strength trainingFigure 6.4
34Assessing Body Fat Distribution Disease risk increases with total waist measurement of more than40 inches for men35 inches for womenDisease risk increases with total waist-to-hip measurement above0.94 for young men0.82 for young womenImage source: Jupiter Images (courtesy of McGraw-Hill Higher Education)
35Estimating 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.
36Jackson and Pollock Three-site Skinfold for Men ChestA diagonal skinfold taken midway between the anterior axillary line and the nippleThighA vertical skinfold taken on the anterior midline of the thigh between the inguinal crease and the proximal border of the patellaAbdomenA vertical skinfold taken 2 cm (~1 inch) to the right of the umbilicus
37Jackson and Pollock Three-site Skinfold for Women TricepsA vertical fold on the posterior midline of the upper arm taken halfway between the acromion and olecranon processesThighA vertical skinfold taken on the anterior midline of the thigh between the inguinal crease and the proximal border of the patellaSuprailiumA 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
38Skinfold Technique: Percent Fat Estimates for Women
39Skinfold Technique: Percent Fat Estimates for Men under 40
40Sample Desired Body Weight Calculation Desired body weight = [Lean body weight / (100% – Desired % fat)] x 100Starting information:Female client’s current weight is 168 pounds, with 28% body fatInitial goal: To achieve 24% body fat without losing lean tissueDetermine fat weight in pounds:Body weight x Body-fat percentage (BF%): 168 lb x 28% = 47 lb of fatDetermine lean body weight (LBW):Total weight – Fat weight: 168 lb – 47 lb = 121 lb of lean tissueCalculate %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
41Making Changes in Body Composition Lifestyle should focus on:Moderate energy intakePhysical activity is the key to long-term successSource: Steve Cole/Getty Images (courtesy of McGraw-Hill Higher Education)
42Chapter 6 Connect Worksheet Chapter 6 Connect Worksheet is due on Monday, October 15th, no later than 11:59PM.