Chapter 9 – Body Composition
Objectives
- What is body composition?
- How does body composition affect a person’s health?
- What are the health risks and costs associated with overweight and obesity?
- What is the significance of body fat distribution?
- What is Body Mass Index (BMI) and why is it important?
Terminology
- Body Composition: The measurement of the body’s proportion of fat mass to fat free mass.
- Fat Mass: The amount of fat tissue in the body often expressed as a percentage of total body mass.
- Fat Free Mass (FFM): not fat tissue in the body such as bones, muscles, ligaments, and blood.
- Essential Fat: the amount of fat needed for vital body functions.
- Non-essential fat: the amount of fat that exceeds the necessary fat needed for vital body functions. This fat is considered energy storage.
- Overweight: the accumulation of non-essential body fat to the point that it adversely affects health.
- Obesity: is characterized by excessive accumulation of body fat and can be defined as a more serious degree of being overweight.
- Adipose Tissue: another term for fat. More specifically it is loose connective tissue composed of adipocytes.
- Subcutaneous fat: fat tissue stored below the skin’s surface.
- Visceral Fat: fat tissue stored around central organs.
- Android shape: a body shape used to help characterize body fat distribution in which fat is stored in the abdominal region. The android shape is also called the “apple” shape.
- Gynoid shape: a body shape used to help characterize body fat distribution in which fat is stored in the hips, buttocks, and thighs. It is also called the pear shape.
- Body Mass Index (BMI): an index based on concept that weight and height should be proportionate. It is calculated by dividing weight by the height squared (weight/height2).
- Hydrodensitometry: This method attempts to measure the density of the body by using water displacement.
- Dual Energy X-ray Absorbtiometry (DEXA): A method of measuring body composition that uses low energy x-rays that also measure bone density.
- Air Displacement Plethysmography: A method of measuring body composition that measures the density of the body by using air displacement.
- Bio-electrical impedance analysis (BIA): A method of measuring body composition by emitting a small electrical current through the body and using the amount of resistance encountered by this current to predict body fat content.
- Skinfold Analysis: A method of measuring body composition by measuring the diameter of pinched skin at various sites on the body.