Nutrition chapter 7

Leptin

A hormone made by adipose tissue in proportion to total fat stores in the body that influences long-term regulation of fat mass. Leptin also influences appetite and the release of insulin.

air displacement

A method for estimating body composition that makes use of the volume of space taken up by a body inside a small chamber (Bod Pod). This tool is also known as air displacement plethysmography.

Underweight

A body mass index below 18.5. The cutoff is less precise than for obesity because this condition has been less studied.

Direct calorimetry

A method of determining a body's energy use by measuring heat released from the body. An insulated metabolic chamber is typically used.

indirect calorimetry

A method to measure energy use by the body by measuring oxygen uptake and carbon dioxide output. Formulas are then used to convert this gas exchange value into energy use, estimating the proportion of energy nutrients that are being oxidized for energy in the fuel mix.

dual energy x-ray absorptiometry (DEXA)

A scientific tool used to measure bone mineral density and body composition.

relapse prevention

A series of strategies used to help prevent and cope with weight-control lapses, such as recognizing high-risk situations and deciding beforehand on appropriate responses.

Brown adipose tissue

A specialized form of adipose (fat) tissue that produces large amounts of heat by metabolizing energy-yielding nutrients without synthesizing much useful energy for the body. The unused energy is released as heat.

Stimulus control

Altering the environment to minimize the stimuli for eating such as removing foods from sight by storing them in kitchen cabinets.

bomb calorimeter

An instrument used to determine the calorie content of a food.

Lean body mass

Body weight minus fat storage weight equals lean body mass. This includes organs such as the brain, muscles, and liver, as well as bone and blood and other body fluids.

Chain breaking

Breaking the link between two or more behaviors that encourage overeating, such as snacking while watching television.

Cognitive reconstruction

Changing one's frame of mind regarding eating; for example, instead of using a difficult day as an excuse to overeat, a person would substitute other pleasures for rewards, such as a relaxing walk with a friend.

contingency management

Forming a plan of action to respond to a situation in which overeating is likely, such as when snacks are within arm's reach at a party.

skinfold measurements

Skinfold or caliper testing; a common method to determine body fat percentage. This utilizes prediction equations that are population specific to estimate fat.

adaptive thermogenesis

The ability of humans to regulate body temperature within narrow limits (thermoregulation) in response to changes in dietary patterns or environmental temperatures.

resting metabolism

The amount of calories the body uses when the person has not eaten in 4 hours and is resting (e.g., 15 to 30 minutes) and awake in a warm, quiet environment. It is usually slightly higher (10%) than basal metabolism due to the less strict criteria for the test; often referred to as resting metabolic rate (RMR).

Thermic effect of food (TEF)

The increase in metabolism that occurs during the digestion, absorption, and metabolism of energy-yielding nutrients. This represents 5% to 10% of calories consumed.

Baristrics

The medical specialty focusing on the treatment of obesity.

bioelectrical impedance (BIA)

The method to estimate total body fat that uses a low-energy electrical current. The more fat storage a person has, the more impedance (resistance) to electrical flow will be exhibited.

Basal metabolism

The minimal amount of calories the body uses to support itself in a fasting state when resting and awake in a warm, quiet environment. It amounts to roughly 1 kcal per kg per hour for men and 0.9 kcal per kg per hour for women; these values are often referred to as basal metabolic rate (BMR).

Positive energy balance

The state in which energy intake is greater than energy expended, generally resulting in weight gain.

Negative energy balance

The state in which energy intake is less than energy expended, resulting in weight loss.

Energy balance

The state in which energy intake, in the form of food and beverages, matches the energy expended, primarily through basal metabolism and physical activity.

upper body (android) obesity

The type of obesity in which fat is stored primarily in the abdominal area; defined as a waist circumference more than 40 inches (102 centimeters) in men and more than 35 inches (88 centimeters) in women; closely associated with a high risk for cardiovascular disease, hypertension, and type 2 diabetes. Also known as visceral or central obesity.

lower body (gynoid) obesity

The type of obesity in which fat storage is primarily located in the buttocks and thigh area. Also known as gynoid or gynecoid obesity.

Set point

Theory of weight status that refers to the close regulation of body weight. Although the details remain unclear, there is evidence that complex mechanisms exist that help regulate weight. Yes

Very low calorie diets (VLCD)

This diet allows a person fewer than 800 calories per day, often in liquid form. Of this, 120 to 480 calories are typically from carbohydrate, and the rest are mostly from high-quality protein.

Underwater (hydrostatic) weighing

This is a method of estimating total body fat by weighing the individual on a standard scale, then weighing him or her again submerged in water. The difference between the two weights is used to estimate total body volume. Also known as hydrodensitometry.

self-monitoring

Tracking foods eaten and conditions affecting eating; actions are usually recorded in a diary, along with location, time, and state of mind. This is a tool to help people understand more about their eating habits.

Identical twins

Two offspring that develop from a single ovum and sperm and, consequently, are born with the same genetic makeup.

Body Mass Index (BMI)

Weight (in kilograms) divided by height (in meters) squared; a value of 25 and above indicates overweight, and a value of 30 and above indicates obesity.