Table of Contents

What Are Overweight and Obesity?

What Causes Overweight and Obesity?

What Are the Health Risks of Overweight and Obesity?

Who Is at Risk for Overweight and Obesity?

What Are the Signs and Symptoms of Overweight and Obesity?

How Are Overweight and Obesity Diagnosed?

How Are Overweight and Obesity Treated?

How Can Overweight and Obesity Be Prevented?

Clinical Trials

Links to Other Information About Overweight and Obesity

What Are Overweight and Obesity?

The terms "overweight" and "obesity" refer to body weight that’s greater than what is considered healthy for a certain height.

The most useful measure of overweight and obesity is body mass index (BMI). BMI is calculated from your height and weight. For more information about BMI, go to "How Are Overweight and Obesity Diagnosed?"

Overview

Millions of Americans and people worldwide are overweight or obese. Being overweight or obese puts you at risk for many health problems. The more body fat that you have and the more you weigh, the more likely you are to develop:

- Coronary heart disease

- High blood pressure

- Type 2 diabetes

- Gallstones

- Breathing problems

- Certain cancers

Your weight is the result of many factors. These factors include environment, family history and genetics, metabolism (the way your body changes food and oxygen into energy), behavior or habits, and more.

You can't change some factors, such as family history. However, you can change other factors, such as your lifestyle habits.

For example, follow a healthy eating plan and keep your calorie needs in mind. Be physically active and try to limit the amount of time that you're inactive.

Weight-loss medicines and surgery also are options for some people if lifestyle changes aren't enough.

Outlook

Reaching and staying at a healthy weight is a long-term challenge for people who are overweight or obese. But it also is a chance to lower your risk for other serious health problems. With the right treatment and motivation, it's possible to lose weight and lower your long-term disease risk.

What Causes Overweight and Obesity?

Lack of Energy Balance

A lack of energy balance most often causes overweight and obesity. Energy balance means that your energy IN equals your energy OUT.

Energy IN is the amount of energy or calories you get from food and drinks. Energy OUT is the amount of energy your body uses for things like breathing, digesting, and being physically active.

To maintain a healthy weight, your energy IN and OUT don't have to balance exactly every day. It's the balance over time that helps you maintain a healthy weight.

- The same amount of energy IN and energy OUT over time = weight stays the same

- More energy IN than energy OUT over time = weight gain

- More energy OUT than energy IN over time = weight loss

Overweight and obesity happen over time when you take in more calories than you use.

Other Causes

An Inactive Lifestyle

Many Americans aren't very physically active. One reason for this is that many people spend hours in front of TVs and computers doing work, schoolwork, and leisure activities. In fact, more than 2 hours a day of regular TV viewing time has been linked to overweight and obesity.

Other reasons for not being active include: relying on cars instead of walking, fewer physical demands at work or at home because of modern technology and conveniences, and lack of physical education classes in schools.

People who are inactive are more likely to gain weight because they don't burn the calories that they take in from food and drinks. An inactive lifestyle also raises your risk for coronary heart disease, high blood pressure, diabetes, colon cancer, and other health problems.

Environment

Our environment doesn't support healthy lifestyle habits; in fact, it encourages obesity. Some reasons include:

- Lack of neighborhood sidewalks and safe places for recreation. Not having area parks, trails, sidewalks, and affordable gyms makes it hard for people to be physically active.

- Work schedules. People often say that they don't have time to be physically active because of long work hours and time spent commuting.

- Oversized food portions. Americans are exposed to huge food portions in restaurants, fast food places, gas stations, movie theaters, supermarkets, and even at home. Some of these meals and snacks can feed two or more people. Eating large portions means too much energy IN. Over time, this will cause weight gain if it isn't balanced with physical activity.

- Lack of access to healthy foods. Some people don't live in neighborhoods that have supermarkets that sell healthy foods, such as fresh fruits and vegetables. Or, for some people, these healthy foods are too costly.

- Food advertising. Americans are surrounded by ads from food companies. Often children are the targets of advertising for high-calorie, high-fat snacks and sugary drinks. The goal of these ads is to sway people to buy these high-calorie foods, and often they do.

Genes and Family History

Studies of identical twins who have been raised apart show that genes have a strong influence on a person's weight. Overweight and obesity tend to run in families. Your chances of being overweight are greater if one or both of your parents are overweight or obese.

Your genes also may affect the amount of fat you store in your body and where on your body you carry the extra fat. Because families also share food and physical activity habits, a link exists between genes and the environment.

Children adopt the habits of their parents. A child who has overweight parents who eat high-calorie foods and are inactive will likely become overweight too. However, if the family adopts healthy food and physical activity habits, the child's chance of being overweight or obese is reduced.

Health Conditions

Some hormone problems may cause overweight and obesity, such as underactive thyroid (hypothyroidism), Cushing's syndrome, and polycystic ovarian syndrome (PCOS).

Underactive thyroid is a condition in which the thyroid gland doesn't make enough thyroid hormone. Lack of thyroid hormone will slow down your metabolism and cause weight gain. You'll also feel tired and weak.

Cushing's syndrome is a condition in which the body's adrenal glands make too much of the hormone cortisol. Cushing's syndrome also can develop if a person takes high doses of certain medicines, such as prednisone, for long periods.

People who have Cushing's syndrome gain weight, have upper-body obesity, a rounded face, fat around the neck, and thin arms and legs.

PCOS is a condition that affects about 5–10 percent of women of childbearing age. Women who have PCOS often are obese, have excess hair growth, and have reproductive problems and other health issues. These problems are caused by high levels of hormones called androgens.

Medicines

Certain medicines may cause you to gain weight. These medicines include some corticosteroids, antidepressants, and seizure medicines.

These medicines can slow the rate at which your body burns calories, increase your appetite, or cause your body to hold on to extra water. All of these factors can lead to weight gain.

Emotional Factors

Some people eat more than usual when they're bored, angry, or stressed. Over time, overeating will lead to weight gain and may cause overweight or obesity.

Smoking

Some people gain weight when they stop smoking. One reason is that food often tastes and smells better after quitting smoking.

Another reason is because nicotine raises the rate at which your body burns calories, so you burn fewer calories when you stop smoking. However, smoking is a serious health risk, and quitting is more important than possible weight gain.

Age

As you get older, you tend to lose muscle, especially if you're less active. Muscle loss can slow down the rate at which your body burns calories. If you don't reduce your calorie intake as you get older, you may gain weight.

Midlife weight gain in women is mainly due to aging and lifestyle, but menopause also plays a role. Many women gain about 5 pounds during menopause and have more fat around the waist than they did before.

Pregnancy

During pregnancy, women gain weight to support their babies’ growth and development. After giving birth, some women find it hard to lose the weight. This may lead to overweight or obesity, especially after a few pregnancies.

Lack of Sleep

Research shows that lack of sleep increases the risk of obesity. For example, one study of teenagers showed that with each hour of sleep lost, the odds of becoming obese went up. Lack of sleep increases the risk of obesity in other age groups as well.

People who sleep fewer hours also seem to prefer eating foods that are higher in calories and carbohydrates, which can lead to overeating, weight gain, and obesity.

Sleep helps maintain a healthy balance of the hormones that make you feel hungry (ghrelin) or full (leptin). When you don't get enough sleep, your level of ghrelin goes up and your level of leptin goes down. This makes you feel hungrier than when you're well-rested.

Sleep also affects how your body reacts to insulin, the hormone that controls your blood glucose (sugar) level. Lack of sleep results in a higher than normal blood sugar level, which may increase your risk for diabetes.

For more information, go to the Health Topics Sleep Deprivation and Deficiency article.

What Are the Health Risks of Overweight and Obesity?

Being overweight or obese isn't a cosmetic problem. These conditions greatly raise your risk for other health problems.

Overweight and Obesity-Related Health Problems in Adults

Coronary Heart Disease

As your body mass index rises, so does your risk for coronary heart disease (CHD). CHD is a condition in which a waxy substance called plaque (plak) builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart.

Plaque can narrow or block the coronary arteries and reduce blood flow to the heart muscle. This can cause angina (an-JI-nuh or AN-juh-nuh) or a heart attack. (Angina is chest pain or discomfort.)

Obesity also can lead to heart failure. This is a serious condition in which your heart can't pump enough blood to meet your body's needs.

High Blood Pressure

Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps blood. If this pressure rises and stays high over time, it can damage the body in many ways.

Your chances of having high blood pressure are greater if you're overweight or obese.

Stroke

Being overweight or obese can lead to a buildup of plaque in your arteries. Eventually, an area of plaque can rupture, causing a blood clot to form.

If the clot is close to your brain, it can block the flow of blood and oxygen to your brain and cause a stroke. The risk of having a stroke rises as BMI increases.

Type 2 Diabetes

Diabetes is a disease in which the body's blood glucose, or blood sugar, level is too high. Normally, the body breaks down food into glucose and then carries it to cells throughout the body. The cells use a hormone called insulin to turn the glucose into energy.

In type 2 diabetes, the body's cells don't use insulin properly. At first, the body reacts by making more insulin. Over time, however, the body can't make enough insulin to control its blood sugar level.

Diabetes is a leading cause of early death, CHD, stroke, kidney disease, and blindness. Most people who have type 2 diabetes are overweight.

Abnormal Blood Fats

If you're overweight or obese, you're at increased risk of having abnormal levels of blood fats. These include high levels of triglycerides and LDL ("bad") cholesterol and low levels of HDL ("good") cholesterol.

Abnormal levels of these blood fats are a risk factor for CHD. For more information about triglycerides and LDL and HDL cholesterol, go to the Health Topics High Blood Cholesterol article.

Metabolic Syndrome

Metabolic syndrome is the name for a group of risk factors that raises your risk for heart disease and other health problems, such as diabetes and stroke.

You can develop any one of these risk factors by itself, but they tend to occur together. A diagnosis of metabolic syndrome is made if you have at least three of the following risk factors:

- A large waistline. This is called abdominal obesity or "having an apple shape." Having extra fat in the waist area is a greater risk factor for CHD than having extra fat in other parts of the body, such as on the hips.

- A higher than normal triglyceride level (or you're on medicine to treat high triglycerides).

- A lower than normal HDL cholesterol level (or you're on medicine to treat low HDL cholesterol).

- Higher than normal blood pressure (or you're on medicine to treat high blood pressure).

- Higher than normal fasting blood sugar (or you're on medicine to treat diabetes).

Cancer

Being overweight or obese raises your risk for colon, breast, endometrial, and gallbladder cancers.

Osteoarthritis

Osteoarthritis is a common joint problem of the knees, hips, and lower back. The condition occurs if the tissue that protects the joints wears away. Extra weight can put more pressure and wear on joints, causing pain.

Sleep Apnea

Sleep apnea is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep.

A person who has sleep apnea may have more fat stored around the neck. This can narrow the airway, making it hard to breathe.

Obesity Hypoventilation Syndrome

Obesity hypoventilation syndrome (OHS) is a breathing disorder that affects some obese people. In OHS, poor breathing results in too much carbon dioxide (hypoventilation) and too little oxygen in the blood (hypoxemia).

OHS can lead to serious health problems and may even cause death.

Reproductive Problems

Obesity can cause menstrual issues and infertility in women.

Gallstones

Gallstones are hard pieces of stone-like material that form in the gallbladder. They're mostly made of cholesterol. Gallstones can cause stomach or back pain.

People who are overweight or obese are at increased risk of having gallstones. Also, being overweight may result in an enlarged gallbladder that doesn't work well.

Overweight and Obesity-Related Health Problems in Children and Teens

Overweight and obesity also increase the health risks for children and teens. Type 2 diabetes once was rare in American children, but an increasing number of children are developing the disease.

Also, overweight children are more likely to become overweight or obese as adults, with the same disease risks.

Who Is at Risk for Overweight and Obesity?

Overweight and obesity affect Americans of all ages, sexes, and racial/ethnic groups. This serious health problem has been growing over the last 30 years.

Adults

According to the National Health and Nutrition Examination Survey (NHANES) 2009–2010, almost 70 percent of Americans are overweight or obese. The survey also shows differences in overweight and obesity among racial/ethnic groups.

- In women, overweight and obesity are highest among non-Hispanic Black women (about 82 percent), compared with about 76 percent for Hispanic women and 64 percent for non-Hispanic White women.

- In men, overweight and obesity are highest among Hispanic men (about 82 percent), compared with about 74 percent for non-Hispanic White men and about 70 percent for non-Hispanic Black men.

Children and Teens

Children also have become heavier. In the past 30 years, obesity has tripled among school-aged children and teens.

According to NHANES 2009–2010, about 1 in 6 American children ages 2–19 are obese. The survey also suggests that overweight and obesity are having a greater effect on minority groups, including Blacks and Hispanics.

What Are the Signs and Symptoms of Overweight and Obesity?

Weight gain usually happens over time. Most people know when they've gained weight. Some of the signs of overweight and obesity include:

- Clothes feeling tight and needing a larger size.

- The scale showing that you've gained weight.

- Having extra fat around the waist.

- A higher than normal body mass index and waist circumference. (For more information, go to "How Are Overweight and Obesity Diagnosed?")

How Are Overweight and Obesity Diagnosed?

The most common way to find out whether you're overweight or obese is to figure out your body mass index (BMI). BMI is an estimate of body fat, and it's a good gauge of your risk for diseases that occur with more body fat.

BMI is calculated from your height and weight. You can use the chart below or the National Heart, Lung, and Blood Institute's (NHLBI's) online BMI calculator to figure out your BMI. Or, you health care provider can measure your BMI.

Body Mass Index for Adults

Use this table to learn your BMI. First, find your height on the far left column. Next, move across the row to find your weight. Weight is measured with underwear but no shoes.

Once you've found your weight, move to the very top of that column. This number is your BMI.

Height

21

22

23

24

25

26

27

28

29

30

31

4'10"

100

105

110

115

119

124

129

134

138

143

148

5'0"

107

112

118

123

128

133

138

143

148

153

158

5'1"

111

116

122

127

132

137

143

148

153

158

164

5'3"

118

124

130

135

141

146

152

158

163

169

175

5'5"

126

132

138

144

150

156

162

168

174

180

186

5'7"

134

140

146

153

159

166

172

178

185

191

198

5'9"

142

149

155

162

169

176

182

189

196

203

209

5'11"

150

157

165

172

179

186

193

200

208

215

222

6'1"

159

166

174

182

189

197

204

212

219

227

235

6'3"

168

176

184

192

200

208

216

224

232

240

248

This table offers a sample of BMI measurements. If you don't see your height and/or weight listed on this table, go the NHLBI's complete Body Mass Index Table.

What Does Body Mass Index Mean?

BMI

18.5–24.9

Normal weight

25.0–29.9

Overweight

30.0–39.9

Obese

40.0 and above

Extreme obesity

Although BMI can be used for most men and women, it does have some limits. It may overestimate body fat in athletes and others who have a muscular build. BMI also may underestimate body fat in older people and others who have lost muscle.

Body Mass Index for Children and Teens

Overweight are obesity are defined differently for children and teens than for adults. Children are still growing, and boys and girls mature at different rates.

BMIs for children and teens compare their heights and weights against growth charts that take age and sex into account. This is called BMI-for-age percentile. A child or teen's BMI-for-age percentile shows how his or her BMI compares with other boys and girls of the same age.

For more information about BMI-for-age and growth charts for children, go to the Centers for Disease Control and Prevention's BMI-for-age calculator.

What Does the BMI-for-Age Percentile Mean?

BMI-for-Age Percentile

Less than 5th percentile

Underweight

5th percentile to less than the 85th percentile

Healthy weight

85th percentile to less than the 95th percentile

Overweight

95th percentile or greater

Obese

Waist Circumference

Health care professionals also may take your waist measurement. This helps screen for the possible health risks related to overweight and obesity in adults.

If you have abdominal obesity and most of your fat is around your waist rather than at your hips, you're at increased risk for coronary heart disease and type 2 diabetes. The risk goes up with a waist size that's greater than 35 inches for women or greater than 40 inches for men.

You also can measure your waist size. To do so correctly, stand and place a tape measure around your middle, just above your hipbones. Measure your waist just after you breathe out.

Specialists Involved

A primary care doctor (or pediatrician for children and teens) will assess your BMI, waist measurement, and overall health risk. If you're overweight or obese, or if you have a large waist size, your doctor should explain the health risks and find out whether you're interested and willing to lose weight.

If you are, you and your doctor can work together to create a treatment plan. The plan may include weight-loss goals and treatment options that are realistic for you.

Your doctor may send you to other health care specialists if you need expert care. These specialists may include:

- An endocrinologist if you need to be treated for type 2 diabetes or a hormone problem, such as an underactive thyroid.

- A registered dietitian or nutritionist to work with you on ways to change your eating habits.

- An exercise physiologist or trainer to figure out your level of fitness and show you how to do physical activities suitable for you.

- A bariatric surgeon if weight-loss surgery is an option for you.

- A psychiatrist, psychologist, or clinical social worker to help treat depression or stress.

How Are Overweight and Obesity Treated?

Successful weight-loss treatments include setting goals and making lifestyle changes, such as eating fewer calories and being physically active. Medicines and weight-loss surgery also are options for some people if lifestyle changes aren't enough.

Set Realistic Goals

Setting realistic weight-loss goals is an important first step to losing weight.

For Adults

- Try to lose 5 to 10 percent of your current weight over 6 months. This will lower your risk for coronary heart disease (CHD) and other conditions.

- The best way to lose weight is slowly. A weight loss of 1 to 2 pounds a week is do-able, safe, and will help you keep off the weight. It also will give you the time to make new, healthy lifestyle changes.

- If you've lost 10 percent of your body weight, have kept it off for 6 months, and are still overweight or obese, you may want to consider further weight loss.

For Children and Teens

- If your child is overweight or at risk for overweight or obesity, the goal is to maintain his or her current weight and to focus on eating healthy and being physically active. This should be part of a family effort to make lifestyle changes.

- If your child is overweight or obese and has a health condition related to overweight or obesity, your doctor may refer you to a pediatric obesity treatment center.

Lifestyle Changes

Lifestyle changes can help you and your family achieve long-term weight-loss success. Example of lifestyle changes include:

- Focusing on balancing energy IN (calories from food and drinks) with energy OUT (physical activity)

- Following a healthy eating plan

- Learning how to adopt healthy lifestyle habits

Over time, these changes will become part of your everyday life.

Calories

Cutting back on calories (energy IN) will help you lose weight. To lose 1 to 2 pounds a week, adults should cut back their calorie intake by 500 to 1,000 calories a day.

- In general, having 1,000 to 1,200 calories a day will help most women lose weight safely.

- In general, having 1,200 to 1,600 calories a day will help most men lose weight safely. This calorie range also is suitable for women who weigh 165 pounds or more or who exercise routinely.

These calorie levels are a guide and may need to be adjusted. If you eat 1,600 calories a day but don't lose weight, then you may want to cut back to 1,200 calories. If you're hungry on either diet, then you may want to add 100 to 200 calories a day.

Very low-calorie diets with fewer than 800 calories a day shouldn't be used unless your doctor is monitoring you.

For overweight children and teens, it's important to slow the rate of weight gain. However, reduced-calorie diets aren't advised unless you talk with a health care provider.

Healthy Eating Plan

A healthy eating plan gives your body the nutrients it needs every day. It has enough calories for good health, but not so many that you gain weight.

A healthy eating plan is low in saturated fat, trans fat, cholesterol, sodium (salt), and added sugar. Following a healthy eating plan will lower your risk for heart disease and other conditions.

Healthy foods include:

- Fat-free and low-fat dairy products, such as low-fat yogurt, cheese, and milk.

- Protein foods, such as lean meat, fish, poultry without skin, beans, and peas.

- Whole-grain foods, such as whole-wheat bread, oatmeal, and brown rice. Other grain foods include pasta, cereal, bagels, bread, tortillas, couscous, and crackers.

- Fruits, which can be fresh, canned, frozen, or dried.

- Vegetables, which can be fresh, canned (without salt), frozen, or dried.

Canola and olive oils, and soft margarines made from these oils, are heart healthy. However, you should use them in small amounts because they're high in calories.

You also can include unsalted nuts, like walnuts and almonds, in your diet as long as you limit the amount you eat (nuts also are high in calories).

The National Heart, Lung, and Blood Institute's "Aim for a Healthy Weight" Patient Booklet provides more information about following a healthy eating plan.

Foods to limit. Foods that are high in saturated and trans fats and cholesterol raise blood cholesterol levels and also might be high in calories. Fats and cholesterol raise your risk for heart disease, so they should be limited.

Saturated fat is found mainly in:

- Fatty cuts of meat, such as ground beef, sausage, and processed meats (for example, bologna, hot dogs, and deli meats)

- Poultry with the skin

- High-fat dairy products like whole-milk cheeses, whole milk, cream, butter, and ice cream

- Lard, coconut, and palm oils, which are found in many processed foods

Trans fat is found mainly in:

- Foods with partially hydrogenated oils, such as many hard margarines and shortening

- Baked products and snack foods, such as crackers, cookies, doughnuts, and breads

- Foods fried in hydrogenated shortening, such as french fries and chicken

Cholesterol mainly is found in:

- Egg yolks

- Organ meats, such as liver

- Shrimp

- Whole milk or whole-milk products, such as butter, cream, and cheese

Limiting foods and drinks with added sugars, like high-fructose corn syrup, is important. Added sugars will give you extra calories without nutrients like vitamins and minerals. Added sugars are found in many desserts, canned fruit packed in syrup, fruit drinks, and nondiet drinks.

Check the list of ingredients on food packages for added sugars like high-fructose corn syrup. Drinks that contain alcohol also will add calories, so it's a good idea to limit your alcohol intake.

Portion size. A portion is the amount of food that you choose to eat for a meal or snack. It's different from a serving, which is a measured amount of food and is noted on the Nutrition Facts label on food packages.

Anyone who has eaten out lately is likely to notice how big the portions are. In fact, over the past 40 years, portion sizes have grown significantly. These growing portion sizes have changed what we think of as a normal portion.

Cutting back on portion size is a good way to eat fewer calories and balance your energy IN. Learn how today's portions compare with those from 20 years ago at the National Heart, Lung, and Blood Institute's Portion Distortion Web pages.

Food weight. Studies have shown that we all tend to eat a constant "weight" of food. Ounce for ounce, our food intake is fairly consistent. Knowing this, you can lose weight if you eat foods that are lower in calories and fat for a given amount of food.

For example, replacing a full-fat food product that weighs 2 ounces with a low-fat product that weighs the same helps you cut back on calories. Another helpful practice is to eat foods that contain a lot of water, such as vegetables, fruits, and soups.

Physical Activity

Being physically active and eating fewer calories will help you lose weight and keep weight off over time. Physical activity also will benefit you in other ways. It will:

- Lower your risk for heart disease, heart attack, diabetes, and cancers (such as breast, uterine, and colon cancers)

- Strengthen your heart and help your lungs work better

- Strengthen your muscles and keep your joints in good condition

- Slow bone loss

- Give you more energy

- Help you relax and better cope with stress

- Allow you to fall asleep more quickly and sleep more soundly

- Give you an enjoyable way to share time with friends and family

The four main types of physical activity are aerobic, muscle-strengthening, bone strengthening, and stretching. You can do physical activity with light, moderate, or vigorous intensity. The level of intensity depends on how hard you have to work to do the activity.

People vary in the amount of physical activity they need to control their weight. Many people can maintain their weight by doing 150 to 300 minutes (2 hours and 30 minutes to 5 hours) of moderate-intensity activity per week, such as brisk walking.

People who want to lose a large amount of weight (more than 5 percent of their body weight) may need to do more than 300 minutes of moderate-intensity activity per week. This also may be true for people who want to keep off weight that they've lost.

You don't have to do the activity all at once. You can break it up into short periods of at least 10 minutes each.

If you have a heart problem or chronic disease, such as heart disease, diabetes, or high blood pressure, talk with your doctor about what types of physical activity are safe for you. You also should talk with your doctor about safe physical activities if you have symptoms such as chest pain or dizziness.

Children should get at least 60 minutes or more of physical activity every day. Most physical activity should be moderate-intensity aerobic activity. Activity should vary and be a good fit for the child's age and physical development.

Many people lead inactive lives and might not be motivated to do more physical activity. When starting a physical activity program, some people may need help and supervision to avoid injury.

If you're obese, or if you haven't been active in the past, start physical activity slowly and build up the intensity a little at a time.

When starting out, one way to be active is to do more everyday activities, such as taking the stairs instead of the elevator and doing household chores and yard work. The next step is to start walking, biking, or swimming at a slow pace, and then build up the amount of time you exercise or the intensity level of the activity.

To lose weight and gain better health, it's important to get moderate-intensity physical activity. Choose activities that you enjoy and that fit into your daily life.

A daily, brisk walk is an easy way to be more active and improve your health. Use a pedometer to count your daily steps and keep track of how much you're walking. Try to increase the number of steps you take each day. Other examples of moderate-intensity physical activity include dancing, gardening, and water aerobics.

For greater health benefits, try to step up your level of activity or the length of time you're active. For example, start walking for 10 to 15 minutes three times a week, and then build up to brisk walking for 60 minutes, 5 days a week.

For more information about physical activity, go to the Department of Health and Human Services "2008 Physical Activity Guidelines for Americans" and the Health Topics Physical Activity and Your Heart article.

Behavioral Changes

Changing your behaviors or habits related to food and physical activity is important for losing weight. The first step is to understand which habits lead you to overeat or have an inactive lifestyle. The next step is to change these habits.

Below are some simple tips to help you adopt healthier habits.

Change your surroundings. You might be more likely to overeat when watching TV, when treats are available at work, or when you're with a certain friend. You also might find it hard to motivate yourself to be physically active. However, you can change these habits.

- Instead of watching TV, dance to music in your living room or go for a walk.

- Leave the office break room right after you get a cup of coffee.

- Bring a change of clothes to work. Head straight to an exercise class on the way home from work.

- Put a note on your calendar to remind yourself to take a walk or go to your exercise class.

Keep a record. A record of your food intake and the amount of physical activity that you do each day will help inspire you. You also can keep track of your weight. For example, when the record shows that you've been meeting your physical activity goals, you'll want to keep it up. A record also is an easy way to track how you're doing, especially if you're working with a registered dietitian or nutritionist.

Seek support. Ask for help or encouragement from your friends, family, and health care provider. You can get support in person, through e-mail, or by talking on the phone. You also can join a support group.

Reward success. Reward your success for meeting your weight-loss goals or other achievements with something you would like to do, not with food. Choose rewards that you'll enjoy, such as a movie, music CD, an afternoon off from work, a massage, or personal time.

Weight-Loss Medicines

Weight-loss medicines approved by the Food and Drug Administration (FDA) might be an option for some people.

If you're not successful at losing 1 pound a week after 6 months of using lifestyle changes, medicines may help. You should only use medicines as part of a program that includes diet, physical activity, and behavioral changes.

Weight-loss medicines might be suitable for adults who are obese (a BMI of 30 or greater). People who have BMIs of 27 or greater, and who are at risk for heart disease and other health conditions, also may benefit from weight-loss medicines.

Sibutramine (Meridia®)

As of October 2010, the weight-loss medicine sibutramine (Meridia®) was taken off the market in the United States. Research showed that the medicine may raise the risk of heart attack and stroke.

Orlistat (Xenical® and Alli®)

Orlistat (Xenical®) causes a weight loss between 5 and 10 pounds, although some people lose more weight. Most of the weight loss occurs within the first 6 months of taking the medicine.

People taking Xenical need regular checkups with their doctors, especially during the first year of taking the medicine. During checkups, your doctor will check your weight, blood pressure, and pulse and may recommend other tests. He or she also will talk with you about any medicine side effects and answer your questions.

The FDA also has approved Alli®, an over-the-counter (OTC) weight-loss aid for adults. Alli is the lower dose form of orlistat. Alli is meant to be used along with a reduced-calorie, low-fat diet and physical activity. In studies, most people taking Alli lost 5 to 10 pounds over 6 months.

Both Xenical and Alli reduce the absorption of fats, fat calories, and vitamins A, D, E, and K to promote weight loss. Both medicines also can cause mild side effects, such as oily and loose stools.

Although rare, some reports of liver disease have occurred with the use of orlistat. More research is needed to find out whether the medicine plays a role in causing liver disease. Talk with your doctor if you’re considering using Xenical or Alli to lose weight. He or she can discuss the risks and benefits with you.

You also should talk with your doctor before starting orlistat if you’re taking blood-thinning medicines or being treated for diabetes or thyroid disease. Also, ask your doctor whether you should take a multivitamin due to the possible loss of some vitamins.

Lorcaserin Hydrochloride (Belviq®) and Qsymia™

In July 2012, the FDA approved two new medicines for chronic (ongoing) weight management. Lorcaserin hydrochloride (Belviq®) and Qsymia™ are approved for adults who have a BMI of 30 or greater. (Qsymia is a combination of two FDA-approved medicines: phentermine and topiramate.)

These medicines also are approved for adults with a BMI of 27 or greater who have at least one weight-related condition, such as high blood pressure, type 2 diabetes, or high blood cholesterol.

Both medicines are meant to be used along with a reduced-calorie diet and physical activity.

Other Medicines

Some prescription medicines are used for weight loss, but aren't FDA-approved for treating obesity. They include:

- Medicines to treat depression. Some medicines for depression cause an initial weight loss and then a regain of weight while taking the medicine.

- Medicines to treat seizures. Two medicines used for seizures, topiramate and zonisamide, have been shown to cause weight loss. These medicines are being studied to see whether they will be useful in treating obesity.

- Medicines to treat diabetes. Metformin may cause small amounts of weight loss in people who have obesity and diabetes. It's not known how this medicine causes weight loss, but it has been shown to reduce hunger and food intake.

Over-the-Counter Products

Some OTC products claim to promote weight loss. The FDA doesn't regulate these products because they're considered dietary supplements, not medicines.

However, many of these products have serious side effects and generally aren't recommended. Some of these OTC products include:

- Ephedra (also called ma huang). Ephedra comes from plants and has been sold as a dietary supplement. The active ingredient in the plant is called ephedrine. Ephedra can cause short-term weight loss, but it also has serious side effects. It causes high blood pressure and stresses the heart. In 2004, the FDA banned the sale of dietary supplements containing ephedra in the United States.

- Chromium. This is a mineral that's sold as a dietary supplement to reduce body fat. While studies haven't found any weight-loss benefit from chromium, there are few serious side effects from taking it.

- Diuretics and herbal laxatives. These products cause you to lose water weight, not fat. They also can lower your body's potassium levels, which may cause heart and muscle problems.

- Hoodia. Hoodia is a cactus that's native to Africa. It's sold in pill form as an appetite suppressant. However, no firm evidence shows that hoodia works. No large-scale research has been done on humans to show whether hoodia is effective or safe.

Weight-Loss Surgery

Weight-loss surgery might be an option for people who have extreme obesity (BMI of 40 or more) when other treatments have failed.

Weight-loss surgery also is an option for people who have a BMI of 35 or more and life-threatening conditions, such as:

- Severe sleep apnea (a condition in which you have one or more pauses in breathing or shallow breaths while you sleep)

- Obesity-related cardiomyopathy (KAR-de-o-mi-OP-ah-thee; diseases of the heart muscle)

- Severe type 2 diabetes

Types of Weight-Loss Surgery

Two common weight-loss surgeries include banded gastroplasty and Roux-en-Y gastric bypass. For gastroplasty, a band or staples are used to create a small pouch at the top of your stomach. This surgery limits the amount of food and liquids the stomach can hold.

For gastric bypass, a small stomach pouch is created with a bypass around part of the small intestine where most of the calories you eat are absorbed. This surgery limits food intake and reduces the calories your body absorbs.

Weight-loss surgery can improve your health and weight. However, the surgery can be risky, depending on your overall health. Gastroplasty has few long-term side effects, but you must limit your food intake dramatically.

Gastric bypass has more side effects. They include nausea (feeling sick to your stomach), bloating, diarrhea, and faintness. These side effects are all part of a condition called dumping syndrome. After gastric bypass, you may need multivitamins and minerals to prevent nutrient deficiencies.

Lifelong medical followup is needed after both surgeries. Your doctor also may recommend a program both before and after surgery to help you with diet, physical activity, and coping skills.

If you think you would benefit from weight-loss surgery, talk with your doctor. Ask whether you're a candidate for the surgery and discuss the risks, benefits, and what to expect.

Weight-Loss Maintenance

Maintaining your weight loss over time can be a challenge. For adults, weight loss is a success if you lose at least 10 percent of your initial weight and you don't regain more than 6 or 7 pounds in 2 years. You also must keep a lower waist circumference (at least 2 inches lower than your waist circumference before you lost weight).

After 6 months of keeping off the weight, you can think about losing more if:

- You've already lost 5 to 10 percent of your body weight

- You're still overweight or obese

The key to losing more weight or maintaining your weight loss is to continue with lifestyle changes. Adopt these changes as a new way of life.

If you want to lose more weight, you may need to eat fewer calories and increase your activity level. For example, if you eat 1,600 calories a day but don't lose weight, you may want to cut back to 1,200 calories. It's also important to make physical activity part of your normal daily routine.

How Can Overweight and Obesity Be Prevented?

Following a healthy lifestyle can help you prevent overweight and obesity. Many lifestyle habits begin during childhood. Thus, parents and families should encourage their children to make healthy choices, such as following a healthy diet and being physically active.

Make following a healthy lifestyle a family goal. For example:

- Follow a healthy eating plan. Make healthy food choices, keep your calorie needs and your family's calorie needs in mind, and focus on the balance of energy IN and energy OUT.

- Focus on portion size. Watch the portion sizes in fast food and other restaurants. The portions served often are enough for two or three people. Children's portion sizes should be smaller than those for adults. Cutting back on portion size will help you balance energy IN and energy OUT.

- Be active. Make personal and family time active. Find activities that everyone will enjoy. For example, go for a brisk walk, bike or rollerblade, or train together for a walk or run.

- Reduce screen time. Limit the use of TVs, computers, DVDs, and videogames because they limit time for physical activity. Health experts recommend 2 hours or less a day of screen time that's not work- or homework-related.

- Keep track of your weight, body mass index, and waist circumference. Also, keep track of your children's growth.

Led by the National Heart, Lung, and Blood Institute, four Institutes from the National Institutes of Health have come together to promote We Can!®—Ways to Enhance Children's Activity & Nutrition.

We Can! is a national education program designed for parents and caregivers to help children 8 to 13 years old maintain a healthy weight. The evidence-based program offers parents and families tips and fun activities to encourage healthy eating, increase physical activity, and reduce time spent being inactive.

Currently, more than 140 community groups around the country are participating in We Can! programs for parents and youth. These community groups include hospitals, health departments, clinics, faith-based organizations, YMCAs, schools, and more.

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® We Can! is a registered trademark of the U.S. Department of Health and Human Services.

Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. For example, this research has uncovered some of the causes of various diseases and conditions, as well as ways to prevent, diagnose, or treat them.

The NHLBI continues to support research aimed at learning more about various diseases and conditions, including overweight and obesity. For example, NHLBI-supported research on overweight and obesity includes studies that:

- Explore how abdominal obesity affects the human heart and its function

- Examine whether environmental strategies and behavioral changes help reduce overeating in obese children

- Compare the effect of three types of beverages—sugar-sweetened, artificially sweetened, and unsweetened—on heart and blood vessel disease risk factors

- Explore how different diets and physical activities affect overweight and obesity

- Look at how family behaviors influence overweight and obesity in children

Much of this research depends on the willingness of volunteers to take part in clinical trials. Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions.

For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you can gain access to new treatments before they're widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don't directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You'll learn about treatments and tests you may receive, and the benefits and risks they may pose. You'll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you'll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to overweight and obesity, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:

- http://clinicalresearch.nih.gov

- www.clinicaltrials.gov

- www.nhlbi.nih.gov/studies/index.htm

- www.researchmatch.org

For more information about clinical trials for children, visit the NHLBI's Children and Clinical Studies Web page.

Links to Other Information About Overweight and Obesity

NHLBI Resources

- Overweight and Obesity (Health Topics)—online version of this eBook

- "Aim for a Healthy Weight" Patient Booklet

- Aim for a Healthy Weight Web Site

- "At-A-Glance: Facts About Healthy Weight"

- "At-A-Glance: Physical Activity and Your Heart"

- Keep the Beat™ Deliciously Healthy Eating

- NHLBI Body Mass Index Calculator (also available in Spanish)

- Obesity Hypoventilation Syndrome (Health Topics)

- Portion Distortion Web Pages

- We Can!® Web pages

- "We Can! Families Finding the Balance: A Parent Handbook" (also available in Spanish)

- "Your Guide to a Healthy Heart"

- "Your Guide to Physical Activity and Your Heart"

- Physical Activity and Your Heart (Health Topics)

Non-NHLBI Resources

- "2008 Physical Activity Guidelines for Americans" (U.S. Department of Health and Human Services (HHS))

- Childhood Overweight and Obesity (Centers for Disease Control and Prevention (CDC))

- ChooseMyPlate.gov (U.S. Department of Agriculture, HHS)

- Obesity (MedlinePlus)

- Overweight and Obesity (CDC)

- Overweight and Obesity: What You Can Do (Office of the Surgeon General, HHS)

- Physical Activity (CDC)

- "The Surgeon General's Call To Action To Prevent and Decrease Overweight and Obesity, 2001" (Office of the Surgeon General, HHS)

- Weight Control Information Network (National Institute of Diabetes and Digestive and Kidney Diseases)

Clinical Trials

- Children and Clinical Studies

- Clinical Trials (Health Topics)

- Current Research (ClinicalTrials.gov)

- NHLBI Clinical Trials

- NIH Clinical Research Trials and You (National Institutes of Health)

- ResearchMatch (funded by the National Institutes of Health)

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™ Keep the Beat is a trademark of HHS.

® We Can! is a registered trademark of HHS.

The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) has developed Health Topics articles for patients, caregivers, and the public. Health Topics articles provide science-based, plain-language information related to heart, lung, and blood diseases and conditions and sleep disorders. The Health Topics website contains articles on diseases, conditions, tests, procedures, and other relevant topics, which you can email, print, and share.