U.S. Department of Health and Human Services

Contact Us

Health Information Center




This glossary defines words that are often used when people talk or write about healthy eating, obesity, physical activity, and weight control. The glossary includes many, but not all words related to these topics. The definitions in this glossary were adapted from several Government sources, including the Medline Plus website of the National Institutes of Health; the Dietary Guidelines for Americans, 2010; the 2008 Physical Activity Guidelines for Americans; and the Centers for Disease Control and Prevention. You may find web links to these and other helpful sources of information on the Resources page.



The information in this glossary is not intended to serve as medical advice. Please speak with your health care provider to discuss any questions or concerns you may have about physical activity, weight control and related diseases and conditions.


Added sugars These sugars, syrups, and other caloric sweeteners are added when foods are processed or prepared. Added sugars do not include sugars that occur naturally, like fructose in fruit or lactose in milk. Names for added sugars include brown sugar, cane sugar, corn sugar, corn sweetener, corn syrup, dextrose, fructose (when not naturally occurring), fruit juice concentrates, glucose, high-fructose corn syrup, honey, invert sugar, lactose (when not in milk or dairy products), maltose, malt syrup, molasses, raw sugar, sucrose, and turbinado sugar.

Adipose tissue (add-ih-POSE) Fat tissue in the body.

Aerobic physical activity
Aerobic (or endurance) physical activities use large muscle groups (back, chest, and legs) to increase heart rate and breathing for an extended period of time. Examples include bicycling, brisk walking, running, and swimming. Federal guidelines recommend that adults get 150 to 300 minutes of aerobic activity a week [see physical activity].



Bariatric surgery (bear-ee-AT-ric) Also known as gastrointestinal surgery or weight-loss surgery, this is surgery on the stomach and/or intestines to help patients with extreme obesity lose weight. Bariatric surgery is a weight-loss method used for people who have a body mass index (BMI) of 40 or more. Surgery may also be an option for people with a BMI between 35 and 40 who have health problems related to obesity like heart disease or type 2 diabetes.

BMI See body mass index.

Body mass index (BMI) BMI is a measure of body weight relative to height. The BMI tool uses a formula that produces a score often used to determine if a person is underweight, at a normal weight, overweight, or obese. For adults, a BMI of 18.5 to 24.9 is considered healthy (or "normal"). A person with a BMI of 25 to 29.9 is considered overweight, and a person with a BMI of 30 or more is considered obese.

Children grow at different rates at different times, so it is not always easy to tell if a child is overweight. BMI charts for children compare their height and weight to other children of their same sex and age. For children ages 2 to19, those who are at or above the 85th percentile are considered overweight. Those who are at or above the 95th percentile are considered obese.

To calculate BMI visit http://nccd.cdc.gov/dnpabmi/Calculator.aspx  for children and http://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm for adults.

Bone-strengthening activity A physical activity that promotes the growth and strength of bones. Examples include weight lifting and push-ups.



Calorie (CAL-or-ee) A unit of energy in food. Carbohydrates, fats, protein, and alcohol in the foods and drinks we eat provide food energy or "calories." Carbohydrates and proteins provide 4 calories per gram, fat has 9 calories per gram, and alcohol has 7 calories per gram.

Calorie balance The balance between calories you get from eating and drinking and those you use up through physical activity and body processes like breathing, digesting food, and, in children, growing.

Carbohydrate(kar-bow-HY-drate) A "carb" is a major source of energy for your body. Your digestive system changes carbohydrates into blood glucose (sugar). Your body uses this sugar to make energy for cells, tissues, and organs, and stores any extra sugar in your liver and muscles for when it is needed. If there is more sugar than the body can use, the liver may also break the sugar down further and store it as body fat.

There are two kinds of carbohydrates—simple or complex. Simple carbohydrates include sugars that are a part of some foods, like fructose in fruit or lactose in milk, as well as sugars that may be added when foods are processed or prepared [see definition of added sugars]. Complex carbohydrates include those that come from legumes, such as peas or beans, starchy vegetables, and whole grain breads and cereals. Many complex carbohydrates are good sources of fiber.

Cholesterol (ko-LES-te-rol) Cholesterol is a fat-like substance that is made by your body and found naturally in animal foods such as dairy products, eggs, meat, poultry, and seafood. Foods high in cholesterol include dairy fats, egg yolks, and organ meats such as liver. Cholesterol is needed to carry out functions such as hormone and vitamin production. It is carried through the blood by [lipoproteins].

Two types of lipoproteins carry cholesterol in the blood: low-density lipoproteins (LDL, often called "bad cholesterol") and high-density lipoproteins (HDL or "good cholesterol"). When cholesterol levels are too high, some of the cholesterol may stick to the walls of your arteries. This build-up is called plaque. Over time, plaque may narrow your arteries or even block them. High levels of cholesterol in the blood may increase your risk of heart disease.



Diabetes (dye-ah-BEE-teez) A person with this disease has blood glucose, or sugar, levels that are above normal levels. Glucose comes from the foods you eat. Insulin is a hormone that helps the glucose get into your cells to give them energy. Diabetes occurs when the body does not make enough insulin or does not use the insulin it makes. Over time, having too much sugar in your blood may cause serious problems. It may damage your eyes, kidneys, and nerves, and may cause heart disease and stroke. Regular physical activity, weight control, and healthy eating may help you control your diabetes. You should also follow your health care provider's advice and, when asked to, monitor your blood sugar level and take prescribed medication. [Also see gestational diabetes, type 1 diabetes, and type 2 diabetes.]

Diet What a person eats and drinks. Any type of eating plan.

Dietary sodium Also called "salt," sodium helps your nerves and muscles work properly. Table salt is made up of sodium and chloride. Your kidneys control how much sodium is in your blood, releasing it when needed and flushing out any excess. If too much sodium builds up in your blood, this may raise your blood pressure. High blood pressure is linked to serious health problems. Federal dietary guidelines http://www.health.gov/dietaryguidelines/ recommend that most people limit their intake of sodium to less than 2,300 milligrams (mg) a day (less than 1 teaspoon of salt).



Energy expenditure The amount of energy that you use measured in calories. You use calories to breathe, send blood through your blood vessels, digest food, maintain posture, and be physically active.

Exercise A type of physical activity that is planned and structured. Exercise is done on purpose to improve or maintain health, physical fitness, and/or physical performance.



Fat A major source of energy in the diet, fat helps the body absorb fat-soluble vitamins, such as vitamins A, D, E, and K. Some kinds of fats, especially saturated fats and trans fatty acids, may raise blood cholesterol and increase the risk for heart disease. Other fats, such as unsaturated fats, do not raise blood cholesterol. Fats that are in foods are combinations of monounsaturated, polyunsaturated, and saturated fatty acids.

Flexibility The range of motion possible at a joint. Flexibility exercises enhance the ability of a joint to move through its full range of motion.



Gastrointestinal surgery (to treat obesity) See bariatric surgery.

Gestational diabetes (jest-AY-shun-ul) (dye-ah-BEE-teez) A type of diabetes that can occur when a woman is pregnant. In the second half of her pregnancy, a woman may have glucose (sugar) in her blood at a level that is higher than normal. In about 95 percent of cases, blood sugar returns to normal after the pregnancy is over. However, women who develop gestational diabetes are at risk for developing type 2 diabetes later in life. [Also see diabetes and type 2 diabetes.]

Glucose (GLU-kos) Glucose is a major source of energy for our bodies and a building block for many carbohydrates [see definition]. The food digestion process breaks down carbohydrates in foods and drinks into glucose. After digestion, glucose is carried in the blood and goes to body cells where it is used for energy or stored.



HDL See high-density lipoprotein.

Healthy weight Healthy weight status is often based on having a body mass index (BMI) that falls in the normal (or healthy) range [see body mass index]. A healthy body weight may lower the chances of developing health problems such as type 2 diabetes and heart disease.

Heart disease Many different types of heart disease exist. The most common cause of heart disease is narrowing or blockage of the blood vessels that supply blood to the heart. This is called coronary artery disease and happens slowly over time. It's the major reason people have heart attacks. Other kinds of heart problems may happen to the valves in the heart, or the heart may not pump well and cause heart failure.

High blood pressure Your blood pressure rises and falls throughout the day. An optimal blood pressure is less than 120/80 mmHg. When blood pressure stays high—greater than or equal to 140/90 mmHg—you have high blood pressure, also called "hypertension." With high blood pressure, the heart works harder, your arteries take a beating, and your chances of a stroke, heart attack, and kidney problems are greater. Uncontrolled high blood pressure may lead to blindness, heart attacks, heart failure, kidney disease, and stroke. Prehypertension is blood pressure between 120 and 139 for the top number, or between 80 and 89 for the bottom number. If your blood pressure is in the prehypertension range, you may be at risk for high blood pressure unless you take action to prevent it.

High-density lipoprotein (HDL) (lip-o-PRO-teen) HDL is a compound made up of fat and protein that carries cholesterol in the blood to the liver, where it is broken down and excreted. Commonly called "good" cholesterol, high levels of HDL cholesterol are linked to a lower risk of heart disease. Men should aim for an HDL of 40 mg/DL or higher. Women should aim for an HDL of 50 mg/DL or higher.

Hydrogenation (high-dro-jen-AY-shun) A chemical process that turns liquid fats (oils) into solid fats, hydrogenation creates a fat called trans fatty acid (also known as "trans fat"). Trans fats are found in frostings, shortening, some margarines, and some commercial baked foods, like cakes, cookies, muffins, and pastries. Eating trans fats may raise heart disease risk. Federal dietary guidelines [found at http://www.health.gov/dietaryguidelines/] recommend keeping trans fat intakes as low as possible.

Hypertension See high blood pressure.



Insulin (IN-sah-lin) A hormone made by the pancreas, insulin helps move glucose (sugar) from the blood to muscles and other tissues. Insulin controls blood sugar levels.



Lactose intolerance A person with this digestive condition has difficulty digesting foods that have lactose, the sugar found in milk and foods made with milk. If you have lactose intolerance, you may feel sick to your stomach after eating these foods. You may also have gas, diarrhea, and/or swelling in your stomach. Eating less food with lactose or using pills or drops to help you digest lactose usually helps. Aged and hard cheeses, fermented milk products (like yogurt), and lactose-free milk and milk products may be easier to digest. You may need to take a calcium supplement if you avoid milk and foods made with milk because they are the most common source of calcium for most people.

LDL See low-density lipoprotein.

Lipoprotein (lip-o-PRO-teen) A compound made up of fat and protein that carries fats and fat-like substances, such as cholesterol, in the blood. [See also high-density lipoprotein and low-density lipoprotein.]

Low-density lipoprotein (LDL) (lip-o-PRO-teen) LDL is a compound made up of fat and protein that carries cholesterol in the blood from the liver to other parts of the body. High levels of LDL cholesterol, commonly called "bad" cholesterol, cause a buildup of cholesterol in the arteries and increase the risk of heart disease. An LDL level of less than 100 mg/dL is considered optimal, 100 to 129 mg/dL is considered near or above optimal, 130 to 159 mg/dL is considered borderline high, 160 to 189 mg/dL is considered high, and 190 mg/dL or greater is considered very high.



Macronutrient (mac-roh-NOO-tree-ent) A macronutrient is any nutrient that the body uses in relatively large amounts. They include carbohydrates, fat, and proteins.These are different from micronutrients, such as vitamins and minerals, which the body needs in smaller amounts.

Metabolic syndrome (meh-TAB-o-lik SIND-rome) A person with metabolic syndrome has a group of medical problems that, when they occur together, may increase the risk of heart disease and diabetes. These problems are a large waist size, high blood pressure, high blood sugar levels, high levels of triglycerides, and low levels of high-density lipoprotein (HDL).

Metabolism (meh-TAB-o-liszm) The process that occurs in the body to turn the food you eat into energy your body can use. 

Monounsaturated fat (mono-un-SATCH-er-ay-ted) This type of fat is found in avocados, canola oil, nuts, olives and olive oil, and seeds. Eating food that has more monounsaturated fat (or "healthy fat") instead of saturated fat (like butter) may help lower cholesterol and reduce heart disease risk. However, monounsaturated fat has the same number of calories as other types of fat and may contribute to weight gain if you eat too much of it.

Muscle-strengthening activity A type of physical activity that promotes the growth and strength of muscles. Examples include lifting weights and doing push-ups and sit-ups. Federal guidelines recommend that adults do activities that strengthen muscles at least twice a week.



Nutrient dense Nutrient-dense foods and drinks provide important vitamins and minerals and relatively few calories. The term "nutrient dense" also means that these foods and drinks have not been processed or prepared in a way that added a lot of calories from refined starches, sodium, solid fats, or sugar. Examples include fat-free and low-fat milk products or substitutes; fruits and vegetables; protein sources such as beans and peas, eggs, lean meats, poultry, seafood, and unsalted nuts and seeds; and whole grains.

Nutrition (new-TRISH-un) (1) The process of the body using food to sustain life. (2) The study of food and diet.



Obesity (oh-BEE-si-tee) Obesity refers to excess body fat. Because body fat is usually not measured directly, a ratio of body weight to height is often used instead. It is defined as BMI [see body mass index]. An adult who has a BMI of 30 or higher is considered obese.

Oils Fats that are liquid at room temperature, oils come from many different plants and from seafood. Some common oils include canola, corn, olive, peanut, safflower, soybean, and sunflower oils. A number of foods are naturally high in oils, such as avocados, olives, nuts, and some fish. Federal dietary guidelines [found at http://www.health.gov/dietaryguidelines encourage Americans to replace solid fats with oils when possible.

Overweight Overweight refers to an excessive amount of body weight that includes muscle, bone, fat, and water. A person who has a body mass index (BMI) of 25 to 29.9 [see body mass index] is considered overweight. It is important to remember that although BMI is related to the amount of body fat, BMI does not directly measure body fat. As a result, some people, such as athletes, may have a BMI that identifies them as overweight even though they do not have excess body fat.



Pancreas (PAN-kree-as) A gland and an organ that makes enzymes to help the body break down and use nutrients in food. The pancreas also produces the hormone insulin and releases it into the bloodstream to help the body control blood sugar levels.

Physical activity Any form of exercise or movement. Physical activity may include planned activities such as walking, running, strength training, basketball, or other sports. Physical activity may also include daily activities such as mowing the lawn, washing the car, taking the stairs instead of the elevator, and walking the dog. Federal guidelines on physical activity recommend that adults get at least 150 minutes (30 minutes a day, 5 days a week) of moderate-intensity physical activity for general health benefits. Adults who wish to lose weight or maintain weight loss may need more physical activity, such as 300 minutes (60 minutes a day, 5 days a week). Children should get at least 60 minutes of moderate-intensity physical activity daily.


Portion size The amount of a food served or eaten in one occasion. A portion is not a standard amount. The amount of food it includes may vary by person and occasion [see serving size].

Protein (PRO-teen) One of the nutrients that provide calories to the body. Protein is an essential nutrient that helps build many parts of the body, including blood, bone, muscle, and skin. Protein provides 4 calories per gram and is found in foods like beans, dairy products, eggs, fish, meat, nuts, poultry, and tofu.



Refined grains Any grain that is not a whole grain is a refined grain. This includes grains and grain products missing the bran, endosperm, and/or germ. Many refined grains are low in fiber and enriched with iron, niacin, riboflavin, and thiamin and fortified with folic acid as required by U.S. regulations. Some examples of refined grain products are white flour, white bread and tortillas, and white rice. 

Registered Dietitian (R.D.) A person who has studied diet and nutrition at a college program approved by the Academy of Nutrition and Dietetics (formerly the American Dietetic Association). To become an R.D., a person must complete 900 hours of supervised practical experience accredited by the Commission on the Accreditation for Dietetics Education and must pass an exam. 




Serving size A standard amount of a food, such as a cup or an ounce.

Sodium See dietary sodium.

Solid fats These types of fats are usually not liquid at room temperature. Solid fats are found in most animal foods but also can be made from vegetable oils through hydrogenation. Some common solid fats in our diet include beef fat, butter, chicken fat, coconut oil, palm oil, pork fat (lard), shortening, and stick margarine. Foods high in solid fats include full-fat (regular) cheese, cream, ice cream, and whole milk; bacon, poultry skin, regular ground beef, sausages, and well-marbled cuts of meats; and many baked goods (such as cookies, crackers, croissants, donuts, and pastries).


Sugar-sweetened beverages Drinks that are sweetened with added sugars often add a large number of calories. These beverages include, but are not limited to, energy and sports drinks, fruit drinks, soda, and fruit juices.



Trans fatty acids A type of fat produced when liquid fats (oils) are turned into solid fats through a chemical process called hydrogenation. Eating a large amount of trans fatty acid, or "trans fats," also raises blood cholesterol and risk of heart disease.

Triglycerides (Try-GLIH-ser-ides) A type of fat in your blood, triglycerides can contribute to the hardening and narrowing of your arteries if levels are too high. This puts you at risk of having a heart attack or stroke. Triglycerides are measured along with cholesterol as part of a blood test. Normal triglyceride levels are below 150 mg/dL. Levels above 200 mg/dL are high.

Type 1 diabetes (dye-ah-BEET-eez) Type 1 diabetes is thought to be an autoimmune disorder that attacks and destroys the cells in the pancreas that produce insulin. (An autoimmune disorder occurs when the body's immune system, which usually helps the body fight diseases, turns against its own tissue.) Type 1 diabetes was known as "insulin-dependent diabetes mellitus," or "juvenile diabetes." Without insulin, the body is not able to use blood sugar (glucose) for energy. To treat the disease, a person must inject insulin, exercise daily, and test blood sugar several times a day.

Type 2 diabetes (dye-ah-BEET-eez) People with type 2 diabetes produce insulin, but either do not make enough insulin or their bodies do not efficiently use the insulin they make. People with type 2 diabetes may be able to control their condition by losing weight through diet and exercise. They may also need to inject insulin or take medicine along with continuing to follow a healthy eating pattern and being physically active on a regular basis. Type 2 diabetes was known as "noninsulin-dependent diabetes" or "adult-onset diabetes" and is the most common form of diabetes. Children and adolescents who are overweight may also be at risk to develop type 2 diabetes.



Unsaturated fat (un-SATCH-er-ay-ted) Unsaturated fats are liquid at room temperature. Vegetable oils are a major source of unsaturated fat in the diet. Unsaturated fats include polyunsaturated fats and monounsaturated fats. Other foods, such as avocados, fatty fish like salmon and tuna, most nuts, and olives are good sources of unsaturated fat.



Very low-calorie diet (VLCD) A VLCD is a diet supervised by a health care professional that typically uses commercially prepared formulas to promote rapid weight loss in some patients who are considered to be obese. People on a VLCD consume about 800 calories a day or less.



Waist circumference Excess fat around the waist and a larger waist size increase the risk of health problems linked to obesity. Women with a waist size of more than 35 inches or men with a waist size of more than 40 inches have a higher risk of developing health problems linked to obesity, such as diabetes, heart disease, and high blood pressure.

Weight control This refers to achieving and maintaining a healthy weight with healthy eating and physical activity

Weight-cycling This refers to losing and gaining weight over and over again.

Whole grains Grains and grain products made from the entire grain seed, usually called the kernel, which consists of the bran, endosperm, and/or germ. If the kernel has been cracked, crushed, or flaked, it must retain nearly the same relative proportions of bran, endosperm, and germ as the original grain in order to be called whole grain. Many, but not all, whole grains are also a source of dietary fiber.

Whole wheat grains Grains and grain products made from the entire wheat kernel [see whole grains.]



The NIDDK would like to thank:
David A. Piccoli, M.D., The Children's Hospital of Philadelphia. Binita M. Kamath, MBBChir., the Hospital for Sick Children, Toronto, Ontario



March 2013