Antioxidant.   A substance that prevents the addition of oxygen in a chemical reaction and may retard the aging process. Vitamins A, C, and E are antioxidants.

Arteriosclerosis.   A process associated with aging characterized by plaque formation inside arteries (blood vessels).

Body Mass Index (BMI).   A calculation based on the weight and height of a person, it is a better assessment of the presence or absence of obesity than other methods.

Calorie.   The unit of heat required to raise the temperature of water to one degree Celsius.

Carbohydrates.   A class of a major food group that includes sugars and starches. Typically they contain only carbon, oxygen, and hydrogen. Carbohydrates are stored in the liver and muscles as glycogen, the storage form of sugar.

Cholesterol.   A compound belonging to a family of substances called sterols, which combine with fats and circulate in the bloodstream.

Complex carbohydrates.   A carbohydrate with multiple molecules of sugar (glucose) attached by chemical bonds.

Diabetes mellitus (Type 1).   A disease characterized by lack of insulin and most commonly seen in young people, also called juvenile diabetes. Lack of insulin causes very elevated blood sugar levels and may cause acidosis.

Diabetes mellitus (Type 2).   A disease characterized by resistance of the cells to the actions of insulin, also resulting in elevated blood-sugar levels. It is most common in obese adults.

Disaccharides.   Sugars containing two simple sugar molecules attached by a bond, examples are fructose and lactose.

Fats.   A class name of a major food group that includes oils and animal fats. Fats are made up of fatty acids.

Fatty acids.   The chemical component of fat. Some are nutritionally essential.

Fiber.   A non-digestible component of complex carbohydrates. Fiber can be insoluble (does not dissolve in water) or soluble. A high-fiber diet is considered to be a healthy diet.

Fructose.   A disaccharide sugar commonly found in fruits and vegetables, it has a modest glycemic index.

Glucagon.   Hormone secreted by the pancreas that helps regulate blood sugar and also helps metabolize stored fat.

Glucose.   The form in which sugar circulates in the bloodstream, it is the body's main source of energy.

Glycemic Index.   A term used to describe a carbohydrate's ability to raise the blood sugar over a period of time after ingestion.

Glycemic load.   A measurement of the effect of an ingested carbohydrate on blood sugar. The amount of the carbohydrate and its glycemic index are used in a formula to obtain the glycemic load (number of grams of the carbohydrate multiplied by the glycemic index).

Glycogen.   A complex form of glucose, which is stored in the body and used to meet energy needs between meals.

HDL Cholesterol.   The form of cholesterol circulating in the bloodstream in the form of high-density lipoproteins, thought to be protective against heart disease.

Hypoglycemia.   The term for low blood sugar. Reactive hypoglycemia can occur several hours after the ingestion of high-glycemic carbohydrates. Spontaneous hypoglycemia can occur with the use of some medications, in association with certain tumors, and in dysfunction of some endocrine organs.

Insulin.   A hormone secreted by the pancreas that controls blood sugar and influences protein synthesis and fat metabolism.

Junk food.   Generally made of high-glycemic carbohydrates and combined with fat. Easily recognizable because it is generally contained in cellophane or other plastic wrappers and is inexpensive.

Lactose.   A disaccharide sugar, which is found in milk, it has a modest glycemic index.

LDL cholesterol.   The form of cholesterol circulating in the blood-stream in the form of low-density lipoproteins; high levels are thought to be a major risk factor for heart disease.

Lipolysis.   The breakdown of stored fat into component fatty acids. This chemical reaction is inhibited by high-circulating insulin levels.

Monounsaturated fats.   Fat molecules which contain only one double bond and are therefore better fats; examples are olive and canola oils. Obesity. The presence of excess body fat, best determined by calculating Body Mass Index.

Omega-3 fatty acids.   Fat found in fish, which has been found to have health benefits such as the lowering of cholesterol.

Phytochemicals.   Chemicals that are derived from plants. Many of these have health benefits.

Proteins.   A class name of a major food group that includes animal proteins (meats) and vegetable proteins (beans, lentils). Proteins are composed of amino acids and are the building blocks of the body.

Refined grains.   Grains which have been milled and processed by removing the bran or outer layer. Most of the fiber and nutrients are re-moved during this process and the glycemic index is high. An example is refined wheat flour.

Saturated fat.   Fat molecules whose carbon atoms are fully saturated with hydrogen atoms. This type of fat is generally found in animals, is thought to be less desirable, and should be restricted in the diet.

Simple sugars.   One-molecule sugars. Examples are glucose, fructose, and galactose.

Sucrose.   A disaccharide sugar commonly found in table sugar.

Whole grains.   Grains that have been only partially milled or processed, thus retaining nutrients and fiber and having a lower glycemic index. An example is stone-ground wheat flour.