Glossary of Weight Loss Terms

Medically Reviewed by Nayana Ambardekar, MD on September 18, 2021
8 min read

5-hydroxytryptophan (5-HTP). Found in some over-the-counter weight loss products, this extract from a West African plant seed contains a contaminant linked to a rare and potentially deadly blood disorder. It has not been proven to effectively promote weight loss.

Adjustable Gastric Banding. A surgical procedure in which a band made of special material is placed around the stomach near its upper end, creating a small pouch and a narrow passage into the larger remainder of the stomach. It can be tightened or loosened over time to change the size of the passage.

Aerobic Exercise. Any activity involving large muscles, done for an extended period of time. Aerobic exercise can be done for weight loss, but it also provides cardiovascular benefits. Examples of aerobic exercise include walking, biking, jogging, swimming, aerobic classes, and cross-country skiing.

Aloe. Herbal product derived from the aloe plant, it is often added to herbal weight loss products. However, it has not been shown to effectively promote permanent weight loss.

Different parts of the aloe plant may be used. Aloe gel may lower blood sugar and keep other drugs from being properly absorbed. Aloe leaf lining has more side effects, including nausea, diarrhea, lowering of potassium in the blood, and laxative effects that could be dangerous to individuals in poor health.

Anaerobic Exercise. This is higher intensity exercise of shorter duration. Examples include weight lifting and body weight exercises like pushups, pullups, situps, squats, etc. Anaerobic exercise promotes lean muscle tissue. Muscle burns more calories, creating a higher metabolic rate and assists with weight loss.

Appetite Suppressants. Weight loss drugs that act upon the brain, "tricking" it into believing that it is not hungry or that it's full.

Bioelectrical Impedance Analysis. A body composition test that works by sending a small electrical signal through the body, enabling the amount of fat, muscle, and other lean tissue to be measured.

Body Composition Test. A test used to determine a person's current percentage of body fat.

Body Mass Index (BMI). A popular method used to gauge whether or not a person is overweight or obese. BMI is calculated by dividing a person's weight (in kilograms or pounds) by their height (in meters or inches).

Calorie. A unit of measure for the amount of energy released when the body breaks down food.

Carbohydrate. Any of a large group of sugars, starches, cellulose, and gums that the body uses by converting into glucose, a simple sugar, for fuel.

Catecholamine. A chemical in the brain that affects mood and appetite.

Chitosan (KITE-o-san). A dietary supplement made from chitin, a starch found in the skeleton of shrimp, crab, and other shellfish. It has not been shown to contribute to permanent weight loss.

Cholesterol. A type of fat that circulates in your blood. It comes from two sources: the body, which makes its own regardless of what is eaten, and from foods containing animal products.

Chromium. This is thought to affect the breakdown of carbohydrates. Several studies have failed to show any benefit in weight loss after taking this nutritional supplement. 

Dietician or Dietitian. A person who specializes in the study of nutrition.

Diuresis. Water loss.

Diuretic. A drug that promotes the formation and excretion of urine.

Duodenum. The beginning portion of the small intestine.

Ephedrine (ma huang). A common ingredient in herbal dietary supplements used for weight loss. Ephedrine can slightly suppress your appetite, but no studies have shown it to be effective in weight loss. Ephedrine is the main active ingredient of ephedra. Ephedra is also known as ma huang, not ephedrine. High doses of ephedra can cause a very fast heartbeat, high blood pressure, irregular heartbeats, stroke, vomiting, psychoses, and even death.

Extensive Gastric Bypass. A gastric bypass operation in which the lower portion of the stomach is removed. The small pouch that remains is connected directly to the final segment of the small intestine, thus completely bypassing both the duodenum and jejunum portions of the small intestine.

Fat. Organic compounds that are made up of carbon, hydrogen, and oxygen, it is the body's most concentrated source of energy. Like protein and carbohydrates, fat is a principal and essential component of the diet.

Fat Absorption Inhibitor. Weight loss drug that works by preventing the body from breaking down and absorbing fat eaten with meals.

Food and Drug Administration (FDA). Government agency whose mission is "to promote and protect the public health by helping safe and effective products reach the market in a timely way, and monitoring products for continued safety after they are in use."

Food Triggers. A situation, such as a holiday party, or emotion, like anger, that causes a person to overeat.

Gastric Bypass. A type of operation that combines the creation of a small stomach pouch to restrict food intake and the construction of bypasses of the duodenum and other segments of the small intestine to cause malabsorption (decreased absorption of nutrients).

Glucomannan. Made from the root of Amorphophallus Konjac, an herbal supplement that is said to contribute to weight loss by delaying the absorption of glucose from the intestines.

Guarana. A nervous system stimulant derived from the seeds of a Brazilian plant of the same name, it is often found in herbal weight loss supplements.

Guar Gum. Also known as guar, guar flour, and jaguar gum, it is a dietary fiber obtained from the Indian cluster bean. Used extensively as a thickening agent for foods and pharmaceuticals, it is commonly sold as an herbal weight loss supplement.

High Protein Diet. Diets that recommend receiving up to 30% of calories (or more) from protein as opposed to the classic diet recommendation of 10%-15%. These diets also recommend receiving 40%-50% of calories from carbohydrates and 20%-30% from fat.

Hydrostatic Body Fat Testing. A body composition test performed by submerging the person in water and then measuring their underwater weight. This is the most reliable means of body fat testing.

Jejunum. The middle section of the small intestine.

Ketone. Waste products in the body that are a result of fat burning.

Ketosis. A secondary metabolic pathway for energy, resulting in an increase of ketones in the blood that are used as energy when carbohydrates or insulin is inadequate. This is dangerous for insulin dependent diabetics. It can also increase the risk of developing kidney stones. Ketosis is prevented by eating at least 100 grams of carbohydrates a day.

Ma Huang.See ephedrine.

Meridia.See Sibutarmine.

Metabolism. The amount of energy (calories) your body burns to maintain itself. Metabolism is the process in which nutrients are acquired, transported, used, and disposed of by the body.

Monounsaturated Fat. A type of fat found in large amounts in foods from plants, including olive, peanut, and canola oil.

Mortality. The rate of death.

Obesity. An excess proportion of total body fat. The most common measure of obesity is the body mass index (BMI). A BMI over 30 is considered obese. However in people with large muscle mass, this could be an overestimate.

Orlistat. A commonly prescribed fat absorption medication, it is sold under the brand name Xenical.

Phen-fen. A weight loss drug made up of fenfluramine and phentermine. Fenfluramine use has been linked to heart valve problems and has been banned by the FDA.

Phenylpropanolamine (PPA). Once a common weight loss ingredient in appetite suppressants, recent studies have linked PPA to an increased risk of stroke. The FDA warns consumers to avoid use of products containing PPA and requested that manufacturers voluntarily discontinue marketing these products.

Polyunsaturated Fat. A type of fat that is found in large amounts in foods from plants, including safflower, sunflower, and corn oil.

Protein. An organic compound that is the "building block" of the human body. Protein builds and maintains muscle tissue.

Pyruvate. Formed in the body during digestion of carbohydrates and protein, some studies indicate that it may help with weight loss. Although it appears to be safe, claims of boosting metabolism, decreasing appetite, and aiding in weight loss require further study.

Qsymia. A long-term prescription weight loss drug that combines two medications: phentermine, an appetite suppressant, and the seizure/migraine drug topiramate. Topiramate causes weight loss in several ways, including increasing feelings of fullness, making foods taste less appealing, and increasing calorie burning.

Recommended Daily Allowance (RDA). The level of essential nutrients required to adequately meet the known nutrient needs of practically all healthy persons, according to the Food and Nutrition Board of the National Academy of Sciences.

Restriction Operation. In this type of weight loss surgery, food intake is restricted by creating a small pouch at the top of the stomach where the food enters from the esophagus. Examples of restriction operations include adjustable gastric banding and vertical banded gastroplasty.

Roux-en-Y Gastric Bypass (RGB). The most common gastric bypass procedure performed in the U.S.

Saturated Fat. A type of fat most often found in animal food products including milk, eggs, meat, and butter. Saturated fat is also found in vegetable products such as coconut and palm oil. Studies show that too much saturated fat in a person's diet increases heart disease risk. There is some controversy regarding plant based saturated fats, such as coconut; as it may act more favorably than animal based saturated fats.

Saxenda. An injectable weight-loss drug that mimics a hormone that helps control blood sugar, insulin levels, and digestion. It may help some obese adults or overweight adults, who also have weight-related medical problems, to lose weight and keep the weight off.

St. John's Wort. There is limited research indicating the supplement's effective use for weight loss.

Serotonin. A neurotransmitter found in the brain that affects mood and appetite.

Sibutramine. A common prescription appetite suppressant. It was sold under the brand name Meridia, which was removed from the market in October 2010.

Vertical-Banded Gastroplasty. A restrictive operation in which a band and staples are used to create a small stomach pouch.

Very Low-Calorie Diet (VLCD). A short-term weight loss diet, VLCDs may be commercially prepared meals of 800 calories or less or low-calorie meal plans. These diets are low in essential nutrients and require vitamin/mineral supplementation.

Weight Cycling. The repeated loss and regain of body weight. When weight cycling is the result of dieting, it is often called "yo-yo" dieting.

Xenical.See Orlistat.

Yerba Mate. Also known as Paraguay tea, this strong central nervous system stimulant is often sold as a dietary supplement. It has not been proven to cause weight loss.