copyright © 2012 the mcgraw-hill companies. all rights reserved. chapter 7 - body composition

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 compositionCopyright © 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)


Fig 7-1 Body composition of young adults (ages 20-24)


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


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


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


Fig 7-2 Visceral and subcutaneous fat in the abdomen


Metabolism

The processes that maintain body functioning. These require energy.

□Resting Metabolic Rate (RMR)(AKA basil metabolic rate)□Dietary thermogenesis□Physical activity


Metabolism


□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


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.


Physical activity

□Energy expended in daily living as well as formal exercise


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


Overweight

□Overweight is excessive weight for height and does not consider body composition

□Based on large-scale population studies


Obesity trends


2009


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”


Gender

□Body composition differs with genders

□Birth weights□Young years□Adolescence and puberty□Mid-life


Fig 7-4 Average percent of body fat by age and gender


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


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


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


Sleep

□Insufficient sleep is associated with increased body fat

□May interfere with the ability to regulate appetite


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


How much sleep is enough?


Why Is Body Composition Important to Know?

□Component of health-related fitness□Some fat is healthy □Having a lot of fat is unhealthy


Risks from Excess Body Fat

□Cardiovascular diseaseIncreased high blood pressureIncreased LDL and triglycerides

□Type 2 diabetesVisceral fat causes problems with

insulin regulation



□CancerIncrease risk of cancer of the breast,

prostate, colon, pancreas, esophagus, endometrium and kidney



□Osteoarthritis□Sleep apnea□asthma□Gall bladder and liver diseases□Reproductive problems


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


Body fat distribution

□Visceral or abdominal fat increases the risk of chronic disease


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


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


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


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


Barbie and Ken


Barbie and Ken: real life?

□Barbie would be 7feet, 5 inches tallWith a 40-inch chest and a 22-inch

waist

□Ken would be 7feet, 8inches tallWith a 50-inch chest and a 43-inch

waist


Fig 7-7 Average young women vs fashion models and Miss America (1920s-2000s)


What to Focus On?

□Positive aspectsYour appearance is only one aspect of

who you are□Health and healthy habitsFocus on healthy eating and physical

activity


What to Focus On?

□RealityThere are some things you can’t

change about yourself□Small and attainable goalsUnrealistic goals can undermine your

efforts to changeFocus on behavior-oriented goals


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.


Assessing Body Composition

□Ideal weight□Percent fat better than scale weight

□BMI□Weight (kg)/Height2 (m)

□BMI does not take into account muscle mass


Fig 7-8 Body mass index


Assessing Body Composition

□How to determine body fat percentage?□Skinfold□Underwater weighing□Bioelectrical impedance analysis□Air displacement plethysmography□Duel X-ray absorptiometry


Making Changes inBody 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


How Much ExerciseIs 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. chapter 7 - body composition

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