Glossary: Obesity

Content provided by the Faculty of the Harvard Medical School

Glossary

bariatric surgery: One of several gastrointestinal operations that cause therapeutic weight loss.

body mass index (BMI): An estimate of an individual's relative body fat calculated from his or her height and weight.

calorie: The unit for measuring the amount of energy in food.

carbohydrate: The major component in fruits, milk, and starches such as bread, pasta, rice, and potatoes. Carbohydrates are one of the three primary nutrients (along with fats and proteins) and provide most of your body's fuel.

diabetes: A chronic metabolic disorder in which levels of blood glucose, or sugar, are elevated. Excess body weight raises the risk of developing this condition.

fat: One of the three major nutrients (along with carbohydrates and proteins). Fat is found in both animal and plant foods; however, fats from different sources have differing chemical compositions and health effects.

fiber: An indigestible substance found in plant foods.

glucose: The body's chief source of energy; a simple sugar that passes easily from the digestive tract into the bloodstream when you consume carbohydrates.

glycemic index: A scale for evaluating foods, based on the rate at which sugar is absorbed into the bloodstream after eating a specific food.

hypertension: High blood pressure. Individuals who are overweight or have obesity are at greater risk of developing high blood pressure.

low-calorie diet: A weight-loss diet that allows only 800–1,500 calories a day.

metabolism: The rate at which your body uses energy, measured in calories.

monounsaturated fats: A type of fat found in peanut oil, canola oil, cashews, peanuts, many other nuts, and avocados.

obesity: Excess body fat, usually defined as a body mass index of 30 or more.

overweight: A condition marked by a body mass index of 25 to 30.

polyunsaturated fat: A type of fat found in corn, soybean, and other vegetable oils. It's also found in seeds, legumes, whole grains, and fatty fish, such as salmon and tuna.

protein: One of the three major nutrients (along with carbohydrates and fats). It is used by the body for building and repairing tissues. Protein is derived primarily from animal sources but can be found in some vegetables as well.

resting energy expenditure: The rate at which you burn calories while at rest. Resting energy expenditure accounts for 60%–75% of daily energy expenditure.

saturated fat: A type of fat found in animal foods, such as meat, poultry skin, butter, and dairy products. Also found in palm and coconut oils.

trans fats: Processed fats that are solid at room temperature and include partially hydrogenated or hydrogenated vegetable oils and shortening. These fats are often found in commercial baked goods.

very low-calorie diet: A weight-loss diet that allows 800 or fewer calories per day (usually followed under medical supervision).

Last updated:	June 20, 2007