body composition body composition involves all components of
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Body Composition
Body composition involves all components of the body including:
Fat massMuscle massBone massWater volume
Body Composition
We’ve talked about muscle mass, so this section will focus on fat management.
Body Composition
ObesityMay be functionally defined as the
percent body fat at which disease risk increases.
Body Composition
Obesity is an excessive amount of body fat relative to body weight and is not synonymous with overweight.
Body Composition
In epidemiological studies:overweight is >120% of desirable
weightbody mass index (BMI) >29.3 for
women and 29.8 for men.
Body Composition
Because these overweight 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
An excessive percentage of body fat is associated with increased risk for development of hypertension, diabetes, CAD, and other chronic diseases.
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 Composition
Recent 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
In addition, obesity often carries negative social stigma and is associated with a reduced physical working capacity.
Body Composition
At the opposite extreme, individuals with too little body fat tend to be malnourished.
Body Composition
These people have a relatively higher risk of fluid-electrolyte imbalances, osteoporosis and osteopenia, bone fractures, muscle wasting, cardiac arrhythmias, and sudden death, edema, and renal and reproductive disorders.
Body Composition
One disease associated with extremely low body fat levels is anorexia nervosa.
Body Composition
Anorexia nervosa is an eating disorder found primarily in females and is characterized by excessive weight loss.
Body Composition
Compared to normal women, anorexics have extremely low body fat levels (8 to 13%), signs of muscle wasting, and less bone mineral content and bone density.
Body Composition
Combating obesity and eating disorders is not an easy task.
Body Composition
Many overweight and obese individuals have incorporated patterns of overeating and physical inactivity into to their lifestyles, while others have developed food and/or exercise addictions.
Body Composition
Many are lured by fad diets and exercise gimmicks, and some resort to extreme behaviors such as avoiding food, bingeing and purging, and exercising compulsively.
Body Composition
Body fat is reduced when a chronic negative caloric balance exists.
Body Composition
It is recommended that both an increase in caloric expenditure through exercise and a decrease in caloric intake be used to accomplish this goal.
Body Composition
Exercise increases energy expenditure and slows the rate of fat-free tissue loss that occurs when a person loses weight by severe caloric restriction.
Body Composition
Exercise also helps maintain the resting metabolic rate and thus the rate of weight loss.
Body Composition
Hormones play an important role in regulating metabolism.
Body Composition
Thyroxine is extremely important in regulating resting metabolic rate.
Underproduction of thyroxine can reduce RMR 30 to 50%.
Body Composition
Growth hormone, epinephrine, norepinephrine, and various sex hormones may elevate RMR as much as 15 to 20%.
Body Composition
These hormones increase during exercise and may be responsible for the elevation in resting metabolic rate after cessation of exercise.
Body Composition
Improper diet, overeating, hormonal disturbances, and physical inactivity may create a positive energy balance, which leads to excessive weight gain and obesity.
Body Composition
Lack of physical activity rather than overeating is a more common cause of obesity in children and adults.
Body Composition
Obese individuals are invariably sedentary and many have had poor experiences with exercise in the past.
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.
Body Composition
The exercise professional should interview the obese participant to determine past exercise history, potential scheduling difficulties, and the locations where exercise might be performed (e.g., sports club, home, street, school gym, or track, etc.)
Body Composition
This may increase adherence to an agreed upon exercise program.
Psychological Issues
Overweight and obesity may be caused by psychological factors.
Psychological Issues
Some overweight and obese individuals use food and eating as a coping mechanism or defense mechanism.
Psychological Issues
Compulsive eaters may eat to cope with feelings of insecurity, anxiety, depression, loneliness, stress, and tension rather than to satisfy hunger.
Psychological Issues
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.
Psychological Issues
Encourage clients with eating disorders to seek psychological counseling.
Body Composition
Obesity is associated with increases in both the number (hyperplasia) and size (hypertrophy) of fat cells.
Body Composition
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.
Body Composition
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.
Body Composition
Similarly, caloric restriction and exercise are effective in reducing fat cell size, but not the number of fat cells.
Body Composition
The key to preventing obesity is to closely monitor the dietary intake and energy expenditure, especially during the adolescent growth spurt and puberty.
Body Composition
This could potentially retard the development of new fat cells and control the size of existing fat cells.
Lifestyle Change
Adoption of a physically active lifestyle.
Adoption of dietary guidelines. (US Dept. of Health and Human
Services, 1995)
Dietary Guidelines
Eat a variety of foods.Balance the food you eat with
physical activity.Choose a diet with plenty of grain
products, vegetables, and fruits.
Dietary Guidelines
Choose a diet low in fat, saturated fat, and cholesterol.
Choose a diet moderate in sugars.Choose a diet moderate in salt and
sodium.
Dietary Guidelines
If you drink alcoholic beverages, do so in moderation.
Behavior Modification
Behavior modification techniques can help people make these lifestyle changes.
Behavior Modification
Exercise specialists, nutritionists, and psychologists need to work together to help their clients, especially obesity prone individuals, modify their physical activity and eating attitudes and behaviors.
Body Comp. - Fat Loss
The initial exercise prescription should be based on low intensity and progressively longer durations of activity.
Body Composition
On the basis of each person’s response to the initial exercise program, the exercise professional should eventually work toward increasing the intensity to bring the person into a target heart rate range suitable for cardiorespiratory conditioning.
Body Composition
The higher intensity will allow for a shorter duration per session, or fewer sessions per week for the same weekly energy expenditure.
Body Composition
In addition, the transition to higher intensity exercise will increase the number of opportunities to incorporate activities that naturally require a high rate of energy expenditure.
Body Composition
However, for many (especially older) obese subjects, a walking or other low intensity exercise program may be all they desire, and movement toward a more intense program may not be warranted.
Body Composition
The needs and goals of the obese subject must be individually matched with the proper exercise program to achieve long-term body composition management.
Caloric Balance
Body composition is determined by a complex set of genetic and behavioral factors.
Caloric Balance
Though the contributing variables are many, the fundamental determinant of body weight and body composition is caloric balance.
Caloric Balance
Caloric balance refers to the difference between caloric intake and caloric expenditure.
Caloric Balance
The First Law of Thermodynamics states that energy is neither created nor destroyed; therefore, body weight is lost when caloric expenditure exceeds caloric intake (negative balance) and weight is gained when the opposite situation exists.
Caloric Balance
One pound of body fat (adipose tissue) is equivalent to approximately 3500 kcal of energy.
Caloric Balance
Although it is predictable that shifts in caloric balance will be accompanied by changes in body weight, the nature of the weight change varies markedly with the specific behaviors that lead to the caloric imbalance.
Caloric Balance
For example, fasting and extreme caloric restriction (starvation and semi-starvation diets) cause substantial losses of water and fat-free tissue.
Caloric Balance
In contrast, an exercise-induced negative caloric balance results in weight loss consisting primarily of fat.
Caloric Balance
High resistance exercise programs may lead to a gain in fat-free weight, while cardiorespiratory endurance training usually results in a maintenance of (or slight increase in) fat-free weight.
Caloric Balance
Both types of programs can contribute to a loss of body fat, although aerobic activity is more efficient because it involves a sustained, high rate of energy expenditure.
Recommendations
For most persons, the optimal approach to fat loss combines a mild caloric restriction with regular endurance exercise and avoids nutritional deficiencies.
Recommendations
A desirable fat loss program is one that meets the following criteria:
Recommendations
1. Provides intake not lower than 1220 kcal/day for normal adults and ensures a proper blend of foods to meet nutritional requirements. (Note: this requirement may not be
appropriate for children, older individuals, and athletes).
Recommendations
2. Includes foods acceptable to the dieter in terms of socio-cultural background, usual habits, taste, costs, and ease in acquisition and preparation.
Recommendations
3. Provides a negative caloric balance (not to exceed 500 to 1000 kcal/day), resulting in gradual weight loss without metabolic derangement, such as ketosis.
Recommendations
4. Results in a maximal weight loss of 1 kg/week.
Recommendations
5. Includes the use of behavior modification techniques to identify and eliminate diet habits that contribute to malnutrition.
Recommendations
6. Includes an exercise program that promotes a daily caloric expenditure of 300 or more kcal.
For many participants, this may be best accomplished with low intensity, long duration exercise, such as walking.
Recommendations
7. Provides that new eating and physical activity habits can be continued for life in order to maintain the achieved lower body weight.
Caution
In designing the exercise component of a weight loss program, the balance between intensity and duration of exercise should be manipulated to promote a high total caloric expenditure (300 to 500 kcal per session and 1000 to 2000 kcal per week for adults).
Caution
Obese individuals are at an increased relative risk for orthopedic injury, and this may require that the intensity recommended for improvement of cardiorespiratory endurance.
Caution
Non-weight bearing activities (and/or rotation of exercise modalities) may be necessary and frequent modifications in frequency and duration may also be required.
Setting Goals
A healthy body weight is based on the client’s present FFM and % BF goal.