body composition. zbody composition involves all components of the body including: yfat mass ymuscle...

Body Composition

Body Composition

Body composition involves all components of the body including: Fat mass Muscle mass Bone mass Water volume

Body Composition

We’ve talked about muscle mass, so this section will focus on fat management.

Body Composition Abnormalities

Obesity Epidemic $33 billion weight-loss industry

$168 billion cost total 33.3% of all U.S. adults are obese - “an

excess of body fat frequently resulting in a significant impairment of health”

~65% are sedentary ~25% of school-aged children are

overweight or obese. 70% chance of early death.

Obesity

Defined as the percent body fat at which disease risk increases.

Obesity

An excessive amount of body fat relative to body weight not synonymous with overweight.

Overweight and Obesity

Body Mass Index (BMI) is the most commonly used measure to define overweight and obesity.

• U.S. Department of Health and Human Services

The Epidemic of Overweight and Obesity

BMI is a measure of weight in relation to height. Weight in Kg divided by height in

meters2 Weight in pounds divided by height in

inches2, multiplied by 703.• U.S. Department of Health and Human Services


National Institutes of Health Clinical Guidelines overweight in adults

BMI between 25 to 29.9 obesity in adults

BMI of 30 or greater.

Health risks are greater with a BMI > 25. • U.S. Department of Health and Human Services


The risk of premature death increases with an increasing BMI.

This increase in mortality tends to be modest until a BMI of 30 is reached.



Overweight and obesity are increasing in both genders and among all population groups.

Body Composition

Because BMI criteria do not take into account the composition of the excess weight, they are limited as indexes of obesity and may result in misclassifications of obesity.

Body Composition

Overweight vs Overfat

Metropolitan Life Insurance Height-Weight Charts

Two-component Model:

Fat massFat-free mass

Criterion Referenced Standards:

College Aged Men WomenUnderfat < 3% <12%Healthy Zones 3-20% 12-30%Overfat >20% > 30%Obese > 25% > 35%

Essential Fat

Necessary for normal physiologic function

Men = ~ 3%

Women = ~ 12%

Non-essential fat

Stored energy

Average for college aged Man = 12% Woman = 12%

Average for College Aged

Male = 15%Female = 24%

Sport specific body fat levels

Movement requiredResistance to movement required

Sprinter Maurice Greene

Body Composition

Combating obesity and eating disorders is not an easy task.

Body Composition

A positive energy balance leads to excessive weight gain and obesity improper diet overeating hormonal disturbances physical inactivity

Body Composition

Lack of physical activity rather than overeating is a more common cause of obesity in children and adults.

Creeping Obesity

Food Intake Activity Levels Basal Metabolic Rate

Body Composition

Obese individuals are invariably sedentary and many have had poor experiences with exercise in the past.

Overweight and Obesity

Among women, the prevalence of overweight and obesity generally is higher in women who are members of racial and ethnic minority populations than in non-Hispanic white women.7

Among men, Hispanics have a higher prevalence of overweight and obesity than non-Hispanic whites or non-Hispanic blacks.



For non-Hispanic men, the prevalence of overweight and obesity among whites is slightly greater than among blacks.



Disparities in prevalence of overweight and obesity also exist based on socioeconomic status.7

For all racial and ethnic groups combined, women of lower socioeconomic status (income <130 percent of the poverty threshold) are approximately 50 percent more likely to be obese than those with higher socioeconomic status (income > 130 percent of the poverty threshold).



Men are about equally likely to be obese whether they are in a low or high socioeconomic group.



The overweight and obesity epidemic is not limited to adults.

The percentage of young people who are overweight has almost doubled in the last 20 years for children aged 6-11 and almost tripled for adolescents aged 12-19.



In children and adolescents, overweight has been defined as a sex- and age- specific BMI at or above the 95th percentile for a reference population, based on Centers for Disease Control and Prevention (CDC) growth charts.


Health Risks of Not Maintaining a Healthy Weight

There is an increase in mortality associated with overweight and obesity.

Approximately 300,000 deaths a year in this country are currently associated with overweight and obesity.29



Morbidity from obesity may be as great as from poverty, smoking, or problem drinking.20


It is also important for individuals who are currently at a healthy weight to strive to maintain it since both modest and large weight gains are associated with significantly increased risk of disease.



For example, a weight gain of 11 to 18 pounds increases a person’s risk for developing type 2 diabetes to twice that of individuals who have not gained weight, while those who gain 44 pounds or more have four times the risk of type 2 diabetes.30



A gain of 10 to 20 pounds resulted in an increased risk of coronary heart disease (which can result in nonfatal heart attacks and death) of 1.25 times in women31 and 1.6 times in men.32

In these studies, weight increases of 22 pounds in men and 44 pounds in women resulted in a increased coronary heart disease risk of 1.75 and 2.65, respectively.



Women with a BMI of 34 or greater, the risk of developing endometrial cancer was increased by more than 6 times.33

Overweight and obesity are also known to exacerbate many chronic conditions such as hypertension and elevated cholesterol.


Body Composition

The prevalence of hypercholesterolemia, hypertension, and Type II diabetes is, respectively 2.9, 2.1, and 2.9 times greater in overweight than in non-overweight persons.

Body CompositionRecent evidence

indicates that “central obesity” is particularly problematic.

Abdominal fat is strongly associated with diseases such as CHD, diabetes, hypertension, and hyperlipidemia.

Body Composition

Android and Gynoid Obesity

Body Composition

Obesity is associated with a reduced physical working capacity.


Overweight and obese individuals also may suffer from social stigmatization, discrimination, and poor body image.


Body Composition

At the opposite extreme, individuals with too little body fat tend to be malnourished.

Body CompositionOne disease

associated with extremely low body fat levels is anorexia nervosa.

Body Composition

Anorexics have a relatively higher risk of

fluid-electrolyte imbalances, osteoporosis and osteopenia, bone fractures, muscle wasting, cardiac arrhythmias, sudden death, edema, and renal and reproductive disorders.

Body Composition

Anorexia nervosa is an eating disorder found primarily in females and is characterized by excessive weight loss.

Body Composition

Anorexics have extremely low body fat levels (8 to 13%), signs of muscle wasting, and less bone mineral content and bone density.


Important consequences of excess weight as well as antecedents of adult disease occur in overweight children and adolescents.

Overweight children and adolescents are more likely to become overweight or obese adults.



Type 2 diabetes, high blood lipids, and hypertension as well as early maturation and orthopedic problems are occurring with increased frequency.

A common consequence of childhood overweight is psychosocial specifically discrimination.34


System Dysfunction Associated with Obesity

Obesity

Cardiovascular Renal Liver

Reproductive

Skeletal

Respiratory Intestinal Pancreas Muscular

Hormonal

Metabolic

Hormones

Hormones play an important role in regulating metabolism.

Hormones

Thyroxine is extremely important in regulating resting metabolic rate.

Underproduction of thyroxine can reduce RMR 30 to 50%.

Hormones

May elevate RMR as much as 15 to 20%. Growth hormone, Epinephrine, Norepinephrine, Various sex hormones

Hormones

These hormones increase during exercise and may be responsible for the elevation in resting metabolic rate after cessation of exercise.

Genetics

Only 10% of children who had normal-weight parents were obese.

Genetics

The probability of being obese is increased to 40% and 80%, respectively, if one parent or both parents are obese.

Genetics

Although these data suggest a strong genetic influence, they do not rule out environmental influences such as eating and exercise habits.

Genetics

Approximately 25% of the variability among individuals in absolute and relative body fat is attributed to genetic factors and 30% is associated with cultural (environmental) factors.

Psychological Issues

Overweight and obesity may be linked to psychological factors.

Some overweight and obese individuals use food and eating as a coping mechanism or defense mechanism.


Compulsive eaters may eat to cope with feelings of insecurity, anxiety, depression, loneliness, stress, and tension rather than to satisfy hunger.


In this case, the individual needs to recognize the fact that he or she is eating compulsively, identify the underlying reasons for this behavior, and take steps to modify these behaviors.


Encourage clients with eating disorders to seek psychological counseling.

Fat Patterning

Sex related patterns

Genetic based patterns

Fat Storage

One door room. Primary storage sites. Secondary storage sites. Hyperplasia vs Hypertrophy

Hyperplasia vs Hypertrophy

Obesity is associated with increases in both the number (hyperplasia) and size (hypertrophy) of fat cells.


An increase in fat cell number occurs rapidly during the last trimester in the womb through

the first year of life, around ages 7-8, and again during adolescence, but remains fairly stable in adulthood

except in cases of morbid obesity.


Fat cells grow in size when excess fat is stored in the cells as triglycerides.

Weight gain in adults is typically characterized by the enlargement of existing fat cells, rather than the creation of new fat cells.


Similarly, caloric restriction and exercise are effective in reducing fat cell size, but not the number of fat cells.


The key to preventing obesity is to closely monitor the dietary intake and energy expenditure, especially during the adolescent growth spurt and puberty.


This could potentially retard the development of new fat cells and control the size of existing fat cells.

body composition. zbody composition involves all components of the body including: yfat mass ymuscle...

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body weight

excess of body fat

percent body fat

body fat relative

misclassifications of

indexes of obesity

department of health

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