Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved. Chapter 7 - Body Composition

Coming Up in this Chapter □Basic composition of your body □Factors that affect your body composition □Relationship between your body composition and your health □Assess your own body composition □Strategies for making changes to your body composition Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Body Composition □Body composition is the ratio between fat and fat-free mass □Fat-free mass includes all tissues exclusive of fat (muscle, bone, organs, fluids) Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Fig 7-1 Body composition of young adults (ages 20-24) Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Good Body Fat □Essential Fat □8-12 percent for females □3-5 percent for males □Necessary for normal body function □Found in the central nervous system, bone marrow and other organs Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Essential fat □Key component of cell membranes □Surrounds nerve fibers in the brain allowing for the transmission of messages □Provides for physiological functioning; to maintain life and reproductive functioning Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Storage fat Visceral fat □Found deep within the abdominal cavity □Surrounds internal organs Subcutaneous fat □found just beneath the skin □Insulates the body and regulates temperature Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Fig 7-2 Visceral and subcutaneous fat in the abdomen Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Metabolism The processes that maintain body functioning. These require energy. □Resting Metabolic Rate (RMR) (AKA basil metabolic rate) □Dietary thermogenesis □Physical activity Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Metabolism Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved. □Resting □Eating □Active

Resting metabolic rate Energy required to maintain essential body processes at rest. □Depends on genetics, body size and body composition □Muscle is more metabolically active than fat □Resistance training increase RMR Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Dietary thermogenesis □The energy required to digest and process food □Literature suggest that a diet high in protein, moderate carbohydrates and low fat is more conducive to weight loss than a diet high in carbohydrates and low fat. Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Physical activity □Energy expended in daily living as well as formal exercise Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Obesity □Obesity is over fatness □Obesity in men is defined as body fat equal to or greater than 25% of total body weight □Obesity in women is defined as body fat equal to or greater than 35% of total body weight Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Overweight □Overweight is excessive weight for height and does not consider body composition □Based on large-scale population studies Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Obesity trends Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

2009 Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Genetics □Influence body size □Amount and distribution of body fat □Resting metabolic rate □Response to exercise □However, it can be difficult to separate the effects of genetic inheritance from the eating and activity habits that you “inherit” Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Gender □Body composition differs with genders □Birth weights □Young years □Adolescence and puberty □Mid-life Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Fig 7-4 Average percent of body fat by age and gender Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Fat Distribution in Men and Women □Android, Most men store fat in the abdomen, lower back, chest, and nape of the neck □Gynoid, Most women store fat in the hips, buttocks, thighs, and breasts Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Age □It is hard to separate the effects of age from use Less physical activity and exercise □Physical activity and exercise, especially resistance training, can maintain muscle mass through the aging process Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Lifestyle and Environment □Energy intake □Consume more calories than you burn and you will gain weight □Physical activity □Daily activity and exercise affects energy balance and body composition Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Sleep □Insufficient sleep is associated with increased body fat □May interfere with the ability to regulate appetite Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Short sleep duration □Increased risk of diabetes and heart problems □Increased risk for psychiatric conditions including depression and substance abuse □Decreased ability to pay attention, react to signals or remember new information Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

How much sleep is enough? Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Why Is Body Composition Important to Know? □Component of health-related fitness □Some fat is healthy □Having a lot of fat is unhealthy Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Risks from Excess Body Fat □Cardiovascular disease Increased high blood pressure Increased LDL and triglycerides □Type 2 diabetes Visceral fat causes problems with insulin regulation Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Risks from Excess Body Fat □Cancer Increase risk of cancer of the breast, prostate, colon, pancreas, esophagus, endometrium and kidney Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Risks from Excess Body Fat □Osteoarthritis □Sleep apnea □asthma □Gall bladder and liver diseases □Reproductive problems Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Overweight and Healthy □Age and weight history □How young and how much weight? □An overweight youngster will be exposed to the effects of overweight for a longer period. □We usually gain fat and weight as we age Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Body fat distribution □Visceral or abdominal fat increases the risk of chronic disease Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Lifestyle □Obese people spend a greater portion of their life with disabilities □Regular exercise can improve body composition and reduce some of the risks associated with over weight Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Female Athlete Triad □Excessive exercise and/or insufficient calorie intake □Low energy level unable to support hormonal function- amenorrhea □Bone health- suppressing hormones that promote bone formation Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Body Composition, Body Image, and Emotional Wellness □Body image—a mental picture of your own body □Body dysmorphic disorder— preoccupation with imagined defect in appearance □Muscle dysmorphia—obsessed with idea that being muscular isn’t enough Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Ideas of Body Image □Family life □Parents criticize the look of their children □Friends and teachers also have influence □Media □Fashion magazines □TV shows and TV commercials □Social networking Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Barbie and Ken Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Barbie and Ken: real life? □Barbie would be 7feet, 5 inches tall With a 40-inch chest and a 22-inch waist □Ken would be 7feet, 8inches tall With a 50-inch chest and a 43-inch waist Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Fig 7-7 Average young women vs fashion models and Miss America (1920s-2000s) Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

What to Focus On? □Positive aspects Your appearance is only one aspect of who you are □Health and healthy habits Focus on healthy eating and physical activity Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

What to Focus On? □Reality There are some things you can’t change about yourself □Small and attainable goals Unrealistic goals can undermine your efforts to change Focus on behavior-oriented goals Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

What to Focus On? □Avoiding negative self-talk don’t compare yourself to others or media ideals □Don’t judge what people say or do is more important then how they look. Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Assessing Body Composition □Ideal weight □Percent fat better than scale weight □BMI □Weight (kg)/Height 2 (m) □BMI does not take into account muscle mass Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Fig 7-8 Body mass index Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Assessing Body Composition □How to determine body fat percentage? □Skinfold □Underwater weighing □Bioelectrical impedance analysis □Air displacement plethysmography □Duel X-ray absorptiometry Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

Making Changes in Body Composition □Set appropriate goals □Focus on Energy Balance □Best way to lose body fat □Lose weight but not body fat □Best exercise to lose body fat Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.

How Much Exercise Is Needed? □To prevent weight gain, exercise 150 minutes per week. □To lose weight, exercise 50 minutes a day. □To lose significant amounts of weight, exercise 300 minutes per week. Copyright © 2012 The McGraw-Hill Companies. All Rights Reserved.