Performance Objectives

After completing Chapter 1, you will be able to:

• Define obesity as an excess of body fat.
   
• Define overweight as excessive body weight in relation to height.
   
• Describe and explain the clinical significance of "apple" and "pear" body shapes.
   
• Describe and calculate the following commonly used measures of obesity:
     - weight-for-height tables
     - waist-to-hip ratio
     - body mass index (BMI)
   
• Identify the waist-to-hip ratios associated with increased health risks for men and women.
   
• Explain why the BMI has become the international measure of choice.
   
• Identify the BMI ranges for normal weight, overweight, obesity, and severe obesity.
   
• Describe the relationship between the BMI and risk for morbidity and mortality.
   
• Use the above measures and concepts in sales conversations.

Glossary

Apple shape: people with fat is located mostly around the abdomen are described as apple-shaped.

Bioelectrical impedance analysis (BIA): measures total body water by sending a harmless amount of an electric current through the body. Mathematical equations translate the percent body water measure into an indirect estimate of body fat and lean body mass.

Body Mass Index (BMI): a measure of obesity, calculated by dividing a person's weight in kilograms by the square of their height in meters.

Comorbidities: risk factors associated with, or caused by, a pathologic condition.

Lean body mass: all the tissues of the body except fat tissue.

Morbidity: the rate of illness; the ratio of sick-to-well in a population.

Mortality: the death rate; usually expressed as the number of deaths per 100,000.

Obesity: the chronic disease characterized by an excess of body fat.

Overweight: excessive total body weight in relation to height.

Pear shape: people whose fat tends to be located in their hips and buttocks are described as pear-shaped.

Subcutaneous fat: fat stored under the skin.

Tomography: a diagnostic technique using X-ray photographs in which the shadows of structures,, before and behind the section under scrutiny, do not show.

Visceral adipose tissue: fat stored in the viscera.

Waist-to-hip ratio: a measure of obesity, calculated by dividing the waist circumference by the hip circumference.

Weight-for-height tables: a variety of tables used to compare weight and height with "normal" standards.

Unit 1: Patient Profile

The life of Susan L. demonstrates an ever increasing tendency toward obesity in the American population. When Susan married, at 24, she was an attractive women 5'3" tall weighing 120 pounds. After the birth of her first child, 3 years later, she gained 15 pounds which she was unable to lose. Then, at age 30, she gave birth to her second child. Again, Susan gained 15 pounds. She weighed 160 pounds by the time she was 34.

In her thirties, Susan tried time and again to lose weight with no success. She'd diet and lose 10 or 15 pounds and then regain the weight within three months. Over years, her weight continued to increase, stabilizing at 180 pounds by age 44.

Now 51, Susan has maintained a weight of between 176 and 181 pounds during the seven years. Although reasonably healthy today, she is at high risk for such serious as diabetes, hypertension, heart disease, some forms of cancer, liver and gall disease.

In the United States, 80% of obese individuals are women!

2: Obesity Versus Overweight

What Is "Obesity?"

Obesity means different things to different people. To most men and women it means to be substantially overweight, or larger than they wish to be.

However, researchers and physicians define obesity as:

• an excess of body fat
• a multifactorial chronic disease that requires medical treatment
• a consequence of excess intake of dietary fat
• an epidemic disease
• a condition associated with other diseases and decreased quality of life
• a major contributor to the costs of health care

From a medical point of view, obesity is not:

• a cultural, commercial or cosmetic problem.
• a large body per se: a muscular person may not be obese by simply being "overweight."

Obesity is an excess of body fat.

What Is "Overweight?"

Overweight refers to excessive total body weight in relation to height, and includes all body tissues (muscle, bone, and fat) as well as water.

A person can be overweight without being obese. An example of this is a bodybuilder who has large amounts of muscle tissue.

Nevertheless, measures of overweight described in this chapter are often used by clinicians as a general indicator of health risks.

 "Overweight" indicates excessive total body weight in relation to height

Unit 3: The Function and Distribution of Body Fat

The Function of Fat:

Everyone needs a certain amount of body fat because it serves three primary functions:

1. to store energy
2. to retain body heat
3. to absorb shocks

Normally, fat represents approximately 20% of body weight in males and 25% in females (See Fig. 1.2).

Fat tissue is the largest and most efficient energy store in our body. The amount of energy that can be metabolized from fat is about twice that of carbohydrates and proteins.

Fat provides approximately twice as much energy as carbohydrates or proteins.

The Anatomical Distribution of Fat:

Most of the fat tissue in people with normal body weight is located under the skin. This energy store is called subcutaneous fat. Overweight and obese individuals tend to carry fat tissue primarily in the viscera. This abdominal fat energy store is called visceral adipose tissue (see Fig. 1.3).

Apples and Pears:

People with fat tissue is located primarily around the abdomen have an "apple" shape, while individuals with a tendency to store fat in the hips and buttocks have a "pear" shape (see Fig. 1.4). In general, men tend toward the apple shape, and women toward the pear. This is not a hard and fast rule, however, for women become more apple-shaped after menopause.

Fig. 1.4: The location of fat in "apple" and "pear" shaped persons. You will learn more about health risks in apple- versus pear-shaped people in Unit 4

                     QUICK CHECK

1. Obesity is: (check one)

[ ] an excess of total body weight in relation to height
[ ] overweight
[ ] an excess of body fat

2. Overweight is:

[ ] an excess of body fat
[ ] an excess of body weight in relation to height
[ ] an excess of muscle tissue

3. Two primary functions of body fat are:

1.to retain body heat
2.to absorb shocks
Name the third: _________________________

4. In males with normal weight, fat represents approximately 20 percent of body weight. What is the percentage of fat in females with normal weight? ____

5. Fat provides half as much energy as carbohydrates and proteins.

[ ] True, or [ ] False

6. Match the term on the left with its correct definition/description on the right.

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