Bariatrics: A branch of medicine that deals with the treatment of obesity.

Body mass index (BMI): A measure of body fat that is the ratio of the weight of the body in kilograms to the square of its height in meters. BMI is a better measure of health risk than actual weight in pounds. The medical terms, overweight and obesity, are based on BMI values. A BMI of between 25 and 30 is defined as overweight, and a BMI of 30 or more is considered obese. The higher your BMI, the greater the risk of developing a weight-related illness.

Calories: The energy contained in food, measured in kilocalories, often described simply as calories.

Chronic: Marked by long duration, by frequent recurrence over a long time, and often by slowly progressing seriousness.

Carbohydrates: A source of energy for the body, especially the brain and the nervous system. The liver breaks down carbohydrates into glucose (blood sugar), which is used for energy by the body. Carbohydrates are classified as simple or complex. Simple carbohydrates have one (single) or two (double) sugars while complex carbohydrates have three or more. Complex carbohydrates, often referred to as starchy foods, include whole grain breads and cereals, starchy vegetables, legumes.

Cushing's Syndrome: A glandular disorder caused by excessive cortisol. It is characterized by obesity and weakening of the muscles.

Diabetes: A disease in which sugar and starch are not properly used by our bodies due to inadequate insulin production (type 1) or decreased sensitivity to insulin (type 2).

Fats: A nutrient that can be classified as either saturated or unsaturated depending on the structure of the long carbon-carbon chains in the fatty acids. Fats that contain no double bonds in their fatty acid chains are saturated fats. These fats, such as butter or animal fat, tend to be solid at room temperature. The consumption of saturated fats has been linked to arteriosclerosis (hardening of the arteries) and heart disease. Unsaturated fats contain some number of double bonds in their structure and are generally liquids at room temperature (also referred to as oils). Unsaturated fats can be either polyunsaturated (many double bonds) or monounsaturated (one or few double bonds). Research suggests that monounsaturated fats such as olive oil and canola oil are beneficial in the fight against heart disease.

Glycemic: The effect of different foods on blood glucose (sugar) levels over a period of time. Some foods may raise blood glucose levels more quickly than other foods containing the same amount of carbohydrates.

Hemoglobin A1C:  The component of red blood cells that carries oxygen to the body's cells, it also carries sugar through the bloodstream. Because the sugar is attached for the life of the cell, which is about four months, a test of hemoglobin A1C shows the average blood glucose level for that period of time.

Hypertension: A condition in adults normally described by a systolic pressure of greater than 140 mmHg or a diastolic pressure greater than 90 mmHg.  Typically, three separate abnormally high readings over a few weeks is necessary to diagnosis this condition.

Hypothyroidism: An under-active thyroid gland; a glandular disorder resulting from insufficient production of thyroid hormones.

Hyperlipidemia: An excess of fats or lipids in the blood.

Leptin: A peptide hormone that is produced by fat cells. It plays a role in body weight regulation by acting on the hypothalamus to suppress appetite and burn fat stored in adipose tissue.

Modest Weight Reduction: In the range of 5 to 10 percent of body weight, prior to dieting. It has been demonstrated to improve obesity-related conditions.

Obesity: A condition characterized by excessive body fat. To most people, obesity means to be very overweight. Health professionals define overweight as an excess amount of body weight that includes muscle, bone, fat, and water. Obesity specifically refers to an excess amount of body fat. Some people, such as bodybuilders or other athletes with a lot of muscle, can be overweight without being obese.

Osteoarthritis: A type of arthritis that causes deterioration of the cartilage in the vertebrae and joints.

Physiology: The organic processes and phenomena of an organism or any of its parts or of a particular bodily process.

Sleep Apnea: The temporary absence of breathing during sleep.  It 's a common condition that affects approximately 25% of middle-aged men and 10% of middle-aged women.