What is obesity?

Being obese means having so much body fat that your health is in danger. Having too much body fat can lead to type 2 diabetes, heart disease, high blood pressure, arthritis, sleep apnea, and stroke.

Because of these risks, it is important to lose weight even if you do not feel bad now. It is hard to change eating habits and exercise habits. But you can do it if you make a plan.

How do you know if you are obese?

You can use a measurement called a body mass index, or BMI, to decide whether your weight is dangerous to your health. The BMI is a combination of your height and weight. If you have a BMI of 30 or higher, your extra weight is putting your health in danger. If you are Asian, your health may be at risk with a BMI of 27.5 or higher.

Use the Interactive Tool: Weight and Health Risks to check your body mass index.

Where you carry your body fat may be as important as how many extra pounds you have. People who carry too much fat around the middle, rather than around the hips, are more likely to have health problems. In women, a waist size of 35 in. (88 cm) or more raises the chance for disease. In men, a waist size of 40 in. (101 cm) or more raises the chance for disease.1 In Asian people, health problems are seen with a smaller waist size. In Asian women, a waist size of 32 in. (80 cm) or more raises the chance for disease. In Asian men, a waist size of 36 in. (90 cm) or more raises the chance for disease.2

What causes obesity?

When you take in more calories than you burn off, you gain weight. How you eat, how active you are, and other things affect how your body uses calories and whether you gain weight.

If your family members are obese, you may have inherited a tendency to gain weight. And your family also helps form your eating and lifestyle habits, which can lead to obesity.

Also, our busy lives make it harder to plan and cook healthy meals. For many of us, it's easier to reach for prepared foods, go out to eat, or go to the drive-through. But these foods are often high in fat and calories. Portions are often too large. Work schedules, long commutes, and other commitments also cut into the time we have for physical activity.

There is no quick fix to being overweight. To lose weight, you must burn more calories than you take in.

You've tried diets, but you always gain the weight back. What can you do?

Focus on health, not diets. Diets are hard to stay on and usually do not work in the long run. It is very hard to stay with a diet that includes lots of big changes in your eating habits.

Instead of a diet, focus on lifestyle changes that will improve your health and achieve the right balance of energy and calories. To lose weight, you need to burn more calories than you take in. You can do it by eating healthy foods in reasonable amounts and becoming more active. And you need to do it every day.

Little steps mean a lot. Losing just 10 lb (4.5 kg) can make a difference in your health.

Make a plan for change. Work with your doctor to create a plan that will work for you. Click here to view an Actionset.Ask family members and friends for help in keeping with your plan. Ask your doctor to recommend a dietitian to help you with meal planning.

When you stray from your plan, do not get upset. Figure out what got you off track and how you can fix it.

How can you stay on your plan for change?

It is hard to change habits. You have to be ready. Make sure this is the right time for you. Are you ready to make a plan and stay on it? Do you have the support of your family and friends? Do you know what your first steps will be? Becoming healthier and staying that way is a lifelong effort.

Most people have more success when they make small changes, one step at a time. For example, you might eat an extra piece of fruit, walk 10 minutes more, or add more vegetables to your meals.

Studies show that people who keep track of what they eat are better at losing weight. Keep a notebook where you can write down everything you eat and drink each day. You may be surprised to see how much you are eating. Use a calorie counter to add up your calories. (You can find calorie counters online and at bookstores.)

As you keep track of calories, look at whether you skip meals, when you eat, how often you eat out, and how many fruits and vegetables you eat. This will help you see patterns that you may want to change.

You may want to write down the amount of physical activity you've had each day and compare the calories you burned to those you took in. Use the Interactive Tool: Calories Burned to see how many calories you burn through daily activities.

Can you take medicines or have surgery?

Surgery and medicines do not work by themselves. Most people also need to make changes in what they eat and how active they are.

Before your doctor will prescribe medicines or surgery, he or she will probably want you to work on diet and activity for at least 6 months. Even if your doctor gives you medicines or recommends surgery, you will need to keep your new healthy habits for the rest of your life.

Frequently Asked Questions

Learning about obesity:

Being diagnosed:

Getting treatment:

Ongoing concerns:

Living with obesity:

Health Tools Health Tools help you make wise health decisions or take action to improve your health.

Health Tools help you make wise health decisions or take action to improve your health.

Decision Points focus on key medical care decisions that are important to many health problems. Decision Points focus on key medical care decisions that are important to many health problems.
  Obesity: Should I have weight-loss surgery?
  Obesity: Should I take weight-loss medicine?
  Obesity: Should I use a diet plan to lose weight?

Actionsets help people take an active role in managing a health condition. Actionsets are designed to help people take an active role in managing a health condition.
  Fitness: Using a pedometer or step counter
  Healthy eating: Changing your eating habits
  Healthy eating: Cutting unhealthy fats from your diet
  Healthy eating: Getting support when changing your eating habits

Interactive tools help people determine health risks, ideal weight, target heart rate, and more. Interactive tools are designed to help people determine health risks, ideal weight, target heart rate, and more.
  Interactive Tool: How Many Calories Did You Burn?
  Interactive Tool: Is Your Weight Increasing Your Health Risks?
  Interactive Tool: What Is Your Child's BMI?


Obesity is a complex disease for which no single cause or cure exists. You gain weight when you take in more calories than you burn off. But obesity is influenced by many other factors, also, including your family history, the type of work you do, your race, and Click here to view an Actionset.your environment.

Overeating is easy in our culture today. Portions at fast-food and other restaurants are "super-sized" to the point that one meal can provide an entire day's worth of calories. Food is also a focal point of social activity. Gatherings of family and friends, work events, and holidays are usually centered around food. And eating can be a comfort when you are depressed or stressed.

Also, people are less active than ever. Some people hate to exercise and others may not have the time. And many of the conveniences we use, such as elevators, cars, and the remote control for the television, cut activity out of our lives.

Even making small changes—like walking your dog—can make a difference. Letting the dog out the door burns 2 calories. Walking the dog for 30 minutes burns 125 calories. Taking the car to a car wash uses 18 calories. Washing and waxing it yourself burns 300.

Use this interactive tool to find out how many calories you burn with typical daily activities and exercise:

Interactive Tool: Calories Burned

Other things can affect our weight, such as family history or genetics. If one of your parents is obese, you are 3 times as likely to be obese as someone with parents of healthy weight.3

Your family's and friends' lifestyles can also affect your weight. If your family or friends eat a lot of high-fat or snack foods, eat at irregular times, and skip meals, you probably will too. And if they are not physically active, you may not be either.

Other things influence your weight and whether you are physically active, including:

  • Low self-esteem. Being overweight or obese may lower your self-esteem and lead to eating as a way to comfort yourself. Repeated failure at dieting also can affect your self-esteem and make it even harder to lose weight.
  • Emotional concerns. Emotional stress, anxiety, or illnesses such as depression or chronic pain can lead to overeating. Some people eat to calm themselves, to avoid dealing with unpleasant tasks or situations, or to dampen negative emotions.
  • Trauma. Distressing events, such as childhood sexual, physical, or emotional abuse; loss of a parent during childhood; or marital or family problems, can contribute to overeating.
  • Alcohol. Alcohol (beer and mixed drinks) is very high in calories.
  • Medicines or medical conditions. Some medical conditions and medicines may also cause weight gain. Examples include having Cushing's syndrome or hypothyroidism or taking certain antidepressants or corticosteroids.

Health Risks of Obesity

How obesity affects your health depends on many things, including your age, gender, where you carry your body fat, and how physically active you are.

Risk for diseases

If you are obese, you are more likely to develop type 2 diabetes, high blood pressure, high cholesterol and triglycerides, coronary artery disease (CAD), stroke, and sleep apnea, among other conditions. If you lose weight, your risk for these conditions is reduced.

Where you carry body fat is important. If fat builds up mostly around your stomach (sometimes called apple-shaped), you are at greater risk for type 2 diabetes, high blood pressure, high cholesterol, and coronary artery disease than people who are lean or people with fat around the hips (sometimes called pear-shaped).

See a chart on BMI, waist size, and risk for disease.
See more information on health problems related to obesity.

Making Changes

To make big changes in your lifestyle, you have to be committed. Ask yourself if this is the right time. Are you ready to make a well thought-out plan and stay with it? Do you have the support of your family and friends? Have you talked with your doctor, and do you know what your first steps will be?

Ask your doctor to help you:

  • Identify things that cause you to gain weight.
  • Identify any medicines you are taking that may make it harder for you to lose weight.
  • Make lifestyle changes instead of dieting.

Your doctor may recommend the following professionals to help you make changes:

  • A registered dietitian can help you determine how many calories you need and how best to get them.
  • An exercise specialist or personal trainer can help you plan a safe and effective exercise program.
  • A counselor or psychiatrist can help if you have an emotional problem such as depression or anxiety, have experienced sexual or physical abuse, have family problems, or abuse drugs or alcohol.
  • A surgeon may be needed if you and your doctor think that obesity (bariatric) surgery is an option.

When you are ready to start making changes, do not take on too much too soon. Anything you can do today that was healthier than yesterday is a step in the right direction.

Set small goals. Your goals should be specific, within your reach, and flexible enough to break once in a while. A goal to be more active and eat better is too general. Instead, make a plan to be active 3 to 4 times per week. Perhaps start with a goal of walking for 15 minutes 3 times a week, and then increase it to 4 times a week. When you reach this goal and it has become routine, set a new one. But realize that you may have setbacks now and then—these do not mean that you have failed.

Think about a time that you were successful in making a change, and remember what motivated you. Try to draw on a similar motivation, and set small, realistic goals. Experiencing success, no matter how small, is important. Each time you meet one of your goals, set another one.

Using a pedometer or step counter can help you set goals and be more active. For more information, see:

Click here to view an Actionset. Fitness: Using a pedometer or step counter.

If you don't think you are ready for making changes, try to pick a date in the future. Make an appointment to see your doctor and discuss whether that time is right for you. In the meantime, think about how you can fit changes into your life.

Exams and Tests

Along with a regular medical checkup, you may have some tests to check on your health.

Your doctor may want to do blood tests to check for type 2 diabetes, thyroid, or liver problems, and high cholesterol or high triglyceride levels.

Your doctor will check your blood pressure, ask about any medicines you are taking, and discuss your medical history and your family's medical history. He or she will ask how active you are, whether you drink alcohol (and how much), your history of weight gain, and how often you have tried to lose weight.

Knowing your waist size along with your body mass index (BMI) can help your doctor check your risk for type 2 diabetes and coronary artery disease (CAD).

Early detection

Doctors use BMI to help screen for unhealthy weight. If you have a BMI of 30 or higher, your extra weight is putting your health in danger. If you are Asian, your health may be at risk with a BMI of 27.5 or higher.2

Use the Interactive Tool: Is Your Weight Increasing Your Health Risks? to find your BMI.

If you have concerns that your child is overweight or at risk of becoming so, ask your doctor to review your child's growth charts and medical history with you. If your child's BMI and growth pattern suggest a weight problem, your doctor will give your child an exam that looks for health problems that can cause weight gain. He or she may ask questions about eating and exercise habits. Regular checkups for health problems will also be important over time.

Use the Interactive Tool: What Is Your Child's BMI? to find out the BMI of your child age 2 or older.

Treatment Overview

Treatment for obesity will be most successful if you create a long-term plan with your doctor. A reasonable goal might be to begin making lifestyle changes by increasing physical activity and limiting calories.

Your initial goal should be to improve your health, not to achieve an ideal weight. Although the “formula” for weight loss—to burn more calories than you take in—is not complicated, it is often hard to achieve and maintain. Along with lifestyle changes, medicines and surgery may be options for some people. The treatment you need depends on your level of obesity, your overall health, and your motivation to lose weight.

Health guidelines suggest that people should make lifestyle changes for at least 6 months before trying medicines or surgery. Your doctor may suggest medicines and surgery earlier if you also have conditions such as coronary artery disease or type 2 diabetes.1

Medicines for obesity work in different ways. Depending on the medicine, they make you feel full sooner, limit your body's ability to absorb fat, or control binge eating. Surgery is used to reduce the size of the stomach and limit how many calories are absorbed by the intestines.

Your doctor may also suggest counseling. If you use food to cope with depression, loneliness, anxiety, or boredom, you need to learn new skills to deal with those feelings.

Initial treatment

Before you begin treatment, decide if you are ready to make the lifestyle changes needed to lose weight. Losing weight and maintaining weight loss can be hard. And it may be hard to find the motivation if you have lost and regained weight several times. Think about successes that you had before and how you were able to achieve them.

If you are not ready to make the changes to lose weight, your doctor may suggest that you set a goal to not gain any more weight or set a date in the future to think again about this decision.

If you are ready, your doctor may suggest losing 10% of your weight at a rate of 1 lb (0.45 kg) to 2 lb (0.9 kg) a week as your first target. Research shows that a 10% weight loss can improve your health.1 It is better that you maintain a small amount of loss rather than lose a lot of weight fast and gain it back.

Changing eating habits: Eating fewer calories while increasing activity is the best way to lose weight. For most adults, a low-calorie diet of 1,200 to 1,500 calories a day for women and 1,500 to 1,800 calories a day for men is recommended for weight loss.

Research shows that limiting calories—not the types of foods you eat—causes more weight loss. For example, cutting only carbohydrate or fat will not cause any more weight loss than a healthful and balanced low-calorie diet.3

Rather than focusing on a particular type of diet, try to eat healthier foods. Don't try to restrict the foods you love. Eat less of them. Eat smaller portions.

For some people, a very low-calorie diet may be considered, but generally it is not recommended. A very low-calorie diet should only be conducted under close medical supervision. Over the long term, a low-calorie diet and a very low-calorie diet have similar results.3, 4

Research on low-carbohydrate diets, such as the Atkins plan, show that weight loss is more likely to result from eating fewer calories and staying with the diet for a long time rather than cutting out the carbohydrate.5

Learn more about popular diets for obesity, such as the Zone, Atkins, and Sugar Busters diets.

A dietitian can show you how to make healthy changes in your diet by helping you:

Increasing activity: Physical activity helps you burn more calories. One of the best ways to increase your activity is by walking. It is an activity that most people can do safely and routinely alone or with family members, friends, coworkers, or pets. And it is easy to work into a daily schedule.

Keep track of your steps with a step counter or pedometer. If you have a desk job, you may be surprised to see how little you move in a typical day. Wearing the step counter will motivate you to accumulate more steps during the day. Start with a goal of increasing your steps by 2,000 steps a day and work up to 10,000 to 12,000. For more information, see:

Click here to view an Actionset. Fitness: Using a pedometer or step counter.

Overall, experts recommend doing either of these things to get and stay healthy:6

  • Do moderate activity for at least 2½ hours a week. Moderate activity is equal to a brisk walk, cycling about 10 to 12 miles per hour (mph), sailing, or shooting baskets. You notice your heart beating faster with this kind of activity.
  • Do vigorous activity for at least 1¼ hours a week. Vigorous activity is equal to jogging, cycling at least 12 mph, cross-country skiing, or playing a basketball game. You breathe rapidly and your heart beats much faster with this kind of activity.

It's fine to be active in blocks of 10 minutes or more throughout your day and week. You can choose to do one or both types of activity.

To find out how many calories are burned during various activities, use the Interactive Tool: Calories Burned calculator.

Talk with your doctor before starting a fitness program. If you have arthritis, you will need to find an activity that does not stress your joints.

For more information on exercise and fitness, see the topic Fitness.

Staying with it:Stress, family, your environment, and other influences can affect your progress. If you stray from your plan one day, get back on track the next day.

Research shows that people who keep track of what they eat and drink each day have more success at losing weight. Start a food journal(What is a PDF document?) , and record everything you eat and drink. Pay attention to portion sizes and use a calorie counter to check calories. You can find a calorie counter at a bookstore or online (see www.caloriecontrol.org or www.nutritiondata.com). People often convince themselves that they don't overeat. Documenting your daily food intake can be eye-opening.

Track your daily activity. Use the Interactive Tool: Calories Burned calculator to learn how many calories you use, or use a pedometer to record the number of steps you take.

Click here to view an Actionset. Fitness: Using a pedometer or step counter
  • Understand the connection between stress and eating: Decide whether you eat to calm yourself.
    • Have you noticed a change in your eating or weight since a change occurred in your lifestyle or stress level?
    • Do you eat when you are not hungry or when you are full?
    • Do you eat (or cook) to avoid dealing with a stressful situation?
    • Do you find food very soothing?
    • Do you use food as a reward?
  • If you eat to relieve stress, stop and think about what is really bothering you and how you could deal with it.
    • Change what you are doing. Take a short walk down the hall or around the block.
    • Call a friend.
    • If you are truly hungry, reach for a healthy meal or snack. Focus on the experience of eating, and enjoy your food.
  • Remove temptations, and think before eating: If you have easy access to a lot of high-fat, high-sugar, tasty foods, it is tempting to eat them. Take a look at your environment, and see what causes you to eat more than you need.
    • Do you sometimes eat without thinking? If so, give your food the attention it deserves. Try eating only at the kitchen table. Avoid eating in front of the television or the computer, at your desk, or while driving your car. Be aware of what you do while you are preparing food. Do you snack on ingredients as you make dinner? Chew gum while you cook so that you will not be tempted to snack on the ingredients.
    • Do you eat whatever is most available because you don't plan ahead? Make it a habit to pack a healthy lunch and snacks the night before.
    • Snack from a plate, not from the package. Plan your snacks just like your meals.
    • Is eating a positive, pleasurable experience for you? Take some time to relax before a meal so that you can eat slowly and enjoy it. Eat your meals with others and make your mealtime enjoyable.
    • Do you try to ignore feelings of hunger and skip meals? This can lead to overeating or eating a high-fat snack later on. Plan for meals and snacks to eat at times when you know you will be hungry. The goal is to eat when you are hungry and not eat when you are not hungry.
  • Avoid straying from your plan: Isolated slips are normal, but try these tips to stay with your plan.
    • Think ahead about situations that may be hard, and visualize how you will deal with them. For example, if you're going to a friend's house to watch a movie, remind yourself that snack food may be served. Bring healthy foods to eat, such as raw vegetables or low-fat crackers.
    • Plan for special occasions and situations. Sometimes social situations, such as holidays, parties, and travel, will entice you to eat more. Eat a healthy snack, such as low-fat yogurt or fruit before these meals. It will help you have the willpower to make healthier choices.

For more information, see the topics Healthy Eating and Weight Management.

Ongoing treatment

See your doctor after 6 months to check your progress. Some people stop losing weight around this time, because their bodies adjust to fewer calories, and their motivation starts to slip.

At this point your doctor may want you to increase your activity and revisit the dietitian to make further changes in your diet. Your goals may switch from losing more weight to keeping the weight off. Staying active is very important for maintaining weight loss.

If you have lost weight but gained it back, don't be discouraged. It is not uncommon to try several times before weight comes off and stays off. Talk to your doctor about starting again. It may be helpful to work with others who are trying to lose weight in a structured program.

If you cannot keep weight off or have not managed to lose 1 lb (0.5 kg) a week, your doctor may want you to add medicines. Weight-loss drugs generally are used along with eating changes and exercise. Use of medicine without lifestyle changes is not likely to have long-term success. Medicines for weight loss include sibutramine, orlistat, and phentermine.

Click here to view a Decision Point. Should I take medicines for obesity?

Treatment if the condition gets worse

If you do not lose weight, continue to gain weight, or have lost weight several times only to regain it, or if your doctor is concerned about a related health problem, you might need to try medicines or surgery.

Weight-loss medicines are not prescribed alone. Diet changes and physical activity are needed for keeping weight off long-term. Without these, when medicine is stopped, weight will return.

Medicines for weight loss include sibutramine, orlistat, and phentermine. These drugs work by making you feel full sooner, lowering your appetite, or limiting the amount of fat your body can absorb.

Click here to view a Decision Point. Should I take medicines for obesity?

Your doctor may suggest surgery if you have not been able to lose weight with other treatments and you are at high risk for developing other health problems because of your weight.

If your body mass index is over 40 or if it is 35 or higher and you have a serious medical problem that is made worse by your weight, one of the following surgeries may be an option:

Click here to view a Decision Point. Should I have surgery to treat obesity?

Health Benefits of Weight Loss

Research shows the following health benefits for weight loss:

  • Weight loss may improve survival in those who have an obesity-related disease, especially type 2 diabetes.3
  • A modest weight loss of 4.4 lb (2 kg) to 9.7 lb (4.4 kg) resulted in a significant lowering of blood pressure.7
  • People with asthma who lost an average of 31.3 lb (14.2 kg) over 1 year showed improved lung function and overall health, and with weight loss, the number of severe asthma episodes (exacerbations) and oral corticosteroid courses were reduced.8
  • People with type 2 diabetes who lost weight had lower blood sugar levels and were able to use less medicine to lower their blood sugar levels.3
  • Sustained weight loss prevented new cases of type 2 diabetes in people who were obese.3
  • People with obstructive sleep apnea who lost as little as 10% of their weight improved their sleep patterns and had less daytime sleepiness.3

Weight-Loss Programs and Strategies

What helps one person lose weight may not work for you. You need to find the right balance of eating and physical activity that you can keep doing or a program that works with your lifestyle.

A recent study suggests that the type of diet you follow is less important than choosing one that you can stay with. Most diets or programs can help you lose weight at first. But you will lose more and have more health benefits if you can keep with it for a longer time.

Tips to help with your weight-loss program

  • Set realistic goals. Many people expect to lose much more weight than is realistic. See questions to think about when setting weight management goals to help you define clear, healthy goals.
  • Find what works best for you. If you do not have time to cook and hate to prepare meals, a program that offers meal replacement bars or shakes may be better for you. Or if you like to prepare meals, finding a plan that includes daily menus and recipes may be best.
  • Get family and friends involved to provide support. Talk to them about why you are changing your diet and physical activity and how important losing weight is to you. Ask them to help by doing exercises and having meals with you, even if they may be eating something different.
  • Identify obstacles to losing weight. Look at your food journal and try to find things that cause you to overeat, such as stress or depression.
  • Remove food temptations such as high-calorie snacks, and replace them with healthier foods such as fruit and low-fat yogurt.
  • Get enough physical activity to burn calories and maintain your weight. To find out how many calories are burned during various activities, see the Interactive Tool: Calories Burned calculator.

Tips to help change how you eat

  • Reduce the amount of calories you eat. But unless your doctor advises it, do not have less than 1,000 calories a day.
  • Find sources of added calories, such as snacking, drinking alcohol, or having soft drinks, and reduce your intake of them.
  • Click here to view an Actionset. Cut fat from your diet.
  • Use lean meats and meat alternatives.
  • Plan your meals and snacks ahead of time. This provides a road map for how you will make changes and helps you set goals, track your progress, and reward yourself.
  • Make healthy fast-food, restaurant, and convenience-food choices to maintain your diet when eating out.
  • Keep unhealthy food out of the house.
  • Eat before you go grocery shopping. This can lower your tendency to buy foods that aren't good for you and can help you avoid impulse shopping (buying things you do not need, just because you see them).

Commercial weight-loss programs

Many commercial weight-loss programs (such as Weight Watchers or Lifesteps) and self-help or support groups (such as Overeaters Anonymous) are available. The quality and effectiveness of these programs vary widely, from reputable obesity clinics associated with hospitals to quick weight-loss schemes that may even harm your health with untested “miracle” products.

More research is needed to prove whether these programs are effective or any better than a self-directed program.9 But some people do better when they have a structured plan to follow or can participate with a group of people.

When considering a commercial weight-loss program, ask questions about the staff's qualifications and whether counseling is offered. Be aware that the advertising strategies for weight-loss programs and products, such as using celebrities and "before and after" pictures, are usually unrealistic.

Click here to view a Decision Point. Obesity: Should I use a diet plan to lose weight?


Most weight-loss medicines for obesity work by making you feel less hungry or making you feel full sooner. They are used together with diet and exercise.

Medicine is generally only used for those who have a body mass index (BMI) of 30 or higher. But they sometimes are used for those with a BMI of 27 or higher who are at risk for high blood pressure, high cholesterol, coronary artery disease, type 2 diabetes, and sleep apnea.1

Medicine Choices

Sibutramine (Meridia) is a prescription medicine that makes you feel full sooner.
Orlistat (Xenical) is a prescription medicine that prevents some of the fat calories you eat from being absorbed in your intestines. Also, orlistat (Alli) is available over the counter. Alli contains half of the medicine that is in Xenical.
Phentermine suppresses your appetite. It is approved only for short-term use.

What to Think About

Phentermine is no longer marketed in Europe because of a possible link with heart and lung problems.

Medicine alone is not as effective as when combined with diet or activity. Most of the results reported in research are for a combination of medicine, diet, and activity.

Medicine does not work for everyone. If you do not lose weight within 4 weeks of using medicine, the medicine probably will not help you.4

Studies report that when medicine is stopped, weight is usually regained.10

Although current weight-loss drugs appear to be safer than previous weight-loss medicines, experts do not know how safe or effective they are beyond 2 years of use.11

Nonprescription weight-loss products are not recommended. Some have dangerous side effects, and others have no proven benefit.

Click here to view a Decision Point. Should I take medicines to treat obesity?


Surgery may be an option if you have a body mass index (BMI) of 40 or more. (Use the Interactive Tool: Weight and Health Risks to calculate your BMI.) It may also be an option if you have a BMI of 35 and another health problem related to your weight, such as diabetes or arthritis.

Gastric bypass surgery may help you live longer. Some studies show that people who have weight-loss surgery have a lower risk of dying from heart problems, diabetes, or cancer.12

The goal of surgery is to cause significant weight loss. This should reduce obesity-related health problems, including type 2 diabetes and high blood pressure.

It is important to remember that you may still be obese or overweight after the surgery. Also, surgery will require you to make extreme changes in how you eat, such as eating only a few ounces of food at a time because the surgery creates a much smaller stomach.

Getting good nutrition is also a problem. So you will probably need to take vitamins and supplements. You will also need to avoid high-calorie drinks, which add calories without nutrients.

Two types of surgery are used to treat obesity. A restrictive operation (such as stomach stapling [vertical banded gastroplasty] or adjustable gastric banding) reduces food intake, usually by decreasing the size of the stomach. A malabsorptive, irreversible operation (such as a Roux-en-Y gastric bypass or a biliopancreatic diversion) makes the stomach smaller and decreases the digestion and absorption of food.

Other types of surgery (including intestinal bypass, jaw wiring, and liposuction) have been used to treat obesity. None have been found to have long-term benefit in the treatment of obesity. They are not recommended because of side effects and poor success rates.

Surgery Choices

Restrictive operation (stomach stapling [vertical banded gastroplasty] or gastric banding). In stomach stapling, an incision is made in the abdomen. Surgical staples and a plastic band are used to create a small pouch at the top of the stomach. With gastric banding, a small band is placed around the upper part of the stomach, creating a small pouch.
Roux-en-Y gastric bypass (the most commonly used). Gastric bypass surgery makes the stomach smaller and allows food to bypass part of the small intestine.
Biliopancreatic diversion (rarely used). Biliopancreatic diversion changes the normal process of digestion by making the stomach smaller and allowing food to bypass part of the small intestine so that you absorb fewer calories.

Nutrition concerns

After surgery, you will only be able to eat or drink very small amounts. For the first week or two, you will be on a liquid diet. When you are able to have solid foods, they will need to be pureed.

You will need to avoid certain foods, depending on which type of surgery you have. Right after surgery, you may not be able to have any liquids that contain sugar. And you may have to avoid milk.

You will also need to learn new ways to eat. You'll need to eat very slowly and chew your food well. If you don't make these changes, you may vomit frequently and have pain. You may also develop nutrition problems and need to take vitamins.

Low calcium and iron levels can be problems. Your bones may weaken and you may develop anemia. Your doctor may recommend calcium, iron, and vitamin supplements.

Some people develop dumping syndrome when they eat or drink simple sugars (found in candy, juices, ice cream, condiments, or soft drinks). Dumping syndrome occurs when food moves too quickly through the stomach and intestines. It can cause shaking, sweating, dizziness, rapid heart rate, and often severe diarrhea. Foods with natural sugars found in fruits, dairy, and vegetables do not usually cause dumping syndrome.

You will not be able to drink for 30 minutes before eating, during your meal, and for 30 minutes after eating.

What to Think About

Click here to view a Decision Point. Should I treat obesity with surgery?

All surgeries have risks. Discuss your treatment options with your doctor to decide what is best for you.

Most people who have surgery to treat obesity quickly begin to lose weight. Weight loss usually continues for about 2 years.

Risks common to all surgeries for weight loss include an infection in the incision, a leak from the stomach into the abdominal cavity or where the intestine is connected (resulting in an infection called peritonitis), and a blood clot that blocks blood flow in the lung (pulmonary embolism). About one-third of all people who have surgery for obesity develop anemia or osteoporosis.3, 13

It is important to compare the risks of being obese with the risks of surgery.

Other Places To Get Help


American Society for Metabolic and Bariatric Surgery
100 Southwest 75th Street
Suite 201
Gainesville, Florida  32607
Phone: (352) 331-4900
Fax: (352) 331-4975
E-mail: info@asbs.org
Web Address: www.asmbs.org

The American Society for Bariatric Surgery provides information on surgery for obesity, including guidelines for surgery and risks and outcomes of surgery. A body mass index calculator is provided as well as links to other Web sites and organizations concerned with obesity.

Centers for Disease Control and Prevention (CDC)
1600 Clifton Road
Atlanta, GA  30333
Phone: 1-800-CDC-INFO (1-800-232-4636)
TDD: 1-888-232-6348
E-mail: cdcinfo@cdc.gov
Web Address: www.cdc.gov

The Centers for Disease Control and Prevention (CDC) is an agency of the U.S. Department of Health and Human Services. The CDC works with state and local health officials and the public to achieve better health for all people. The CDC creates the expertise, information, and tools that people and communities need to protect their health—by promoting health, preventing disease, injury, and disability, and being prepared for new health threats.

National Heart, Lung, and Blood Institute (NHLBI)
P.O. Box 30105
Bethesda, MD  20824-0105
Phone: (301) 592-8573
Fax: (240) 629-3246
TDD: (240) 629-3255
E-mail: nhlbiinfo@nhlbi.nih.gov
Web Address: www.nhlbi.nih.gov

The U.S. National Heart, Lung, and Blood Institute (NHLBI) information center offers information and publications about preventing and treating:

  • Diseases affecting the heart and circulation, such as heart attacks, high cholesterol, high blood pressure, peripheral artery disease, and heart problems present at birth (congenital heart diseases).
  • Diseases that affect the lungs, such as asthma, chronic obstructive pulmonary disease (COPD), emphysema, sleep apnea, and pneumonia.
  • Diseases that affect the blood, such as anemia, hemochromatosis, hemophilia, thalassemia, and von Willebrand disease.

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Building 31, Room 9A06
31 Center Drive, MSC 2560
Bethesda, MD  20892-2560
Phone: (301) 496-3583
Web Address: www.niddk.nih.gov

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) provides information and conducts research on a wide variety of diseases as well as issues such as weight control and nutrition.

Overeaters Anonymous (OA)
P.O. Box 44020
Rio Rancho, NM  87174-4020
Phone: (505) 891-2664 (or check the White Pages for a local number)
Fax: (505) 891-4320
E-mail: info@oa.org
Web Address: www.oa.org

Overeaters Anonymous (OA) is a nonprofit international organization that sponsors a 12-step program to help people understand and overcome compulsive eating disorders. OA is not a weight-loss program and makes no claims for weight loss. The program focuses on the psychological and social aspects of overeating.

Shape Up America!
P.O. Box 15009 Native Dancer Road
North Potomac, MD  20878
Phone: (240) 715-3900
E-mail: info@shapeup.org
Web Address: www.shapeup.org

Shape Up America! is a national coalition of industry and medical experts in nutrition and fitness. Its goals are to make Americans more aware of the importance of maintaining a healthy weight and to provide information about how to lose weight and stay fit. The organization has published several booklets on weight loss and diet, which can be ordered from the Web site.

Weight-Control Information Network (WIN)
1 WIN Way
Bethesda, MD  20892-3665
Phone: 1-877-946-4627 toll-free
Fax: (202) 828-1028
E-mail: win@info.niddk.nih.gov
Web Address: http://win.niddk.nih.gov/index.htm

The Weight-control Information Network (WIN) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases, part of the National Institutes of Health. WIN supplies information on weight control, obesity, and nutritional disorders for the public and for health professionals.



  1. National Heart, Lung, and Blood Institute, National Institutes of Health (2000). The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults (NIH Publication No. 00-4084). Available online: http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf.
  2. Purnell JQ (2008). Obesity. In DC Dale, DD Federman, eds., ACP Medicine, section 3, chap. 10. Hamilton, ON: BC Decker.
  3. American Gastroenterological Association (2002). AGA technical review on obesity. Gastroenterology, 123(3): 882–932. [Erratum in Gastroenterology, 123(5): 1752.
  4. Klien S, Romijin JA (2008). Obesity. In HM Kroneberg et al., eds., Williams Textbook of Endocrinology, 11th ed, pp. 1563–1587. Philadelphia: Saunders.
  5. Bravata DM, et al. (2003). Efficacy and safety of low-carbohydrate diets: A systematic review. JAMA, 289(14): 1837–1850.
  6. U.S. Department of Health and Human Services (2008). 2008 Physical Activity Guidelines for Americans (ODPHP Publication No. U0036). Washington, DC: U.S. Government Printing Office. Available online: http://www.health.gov/paguidelines/pdf/paguide.pdf.
  7. Stevens VJ, et al. (2001). Long-term weight loss and changes in blood pressure: Results of the trials of hypertension prevention, phase II. Annals of Internal Medicine 134(1): 1–11.
  8. Stenius-Aarniala B, et al. (2000). Immediate and long-term effects of weight reduction in obese people with asthma: Randomised controlled study. BMJ, 320(7238): 827–832.
  9. Tsai AG, Wadden TA, (2005). Systematic review: An evaluation of major commercial weight loss programs in the United States. Annals of Internal Medicine, 142(1): 56–67.
  10. Hensrud DD (2000). Pharmacotherapy for obesity. Medical Clinics of North America, 84(2): 463–476.
  11. Yanovski SZ, Yanovski JA (2002). Drug therapy: Obesity. New England Journal of Medicine, 346(8): 591–602.
  12. Adams TD, et al. (2007). Long-term mortality after gastric bypass surgery. JAMA, 357(8): 753–761.
  13. U.S. Department of Health and Human Services (2008). Bariatric Surgery for Severe Obesity (NIH Publication No. 04-4006). Available online: http://www.win.niddk.nih.gov/publications/gastric.htm.

Other Works Consulted

  • Elliot K (2003). Nutritional considerations after bariatric surgery. Critical Care Nursing Quarterly, 26(2): 133–158.
  • Flier JS, Maratos-Flier E (2008). Biology of obesity. In AS Fauci et al., eds., Harrison's Principles of Internal Medicine, 17th ed., vol. 1, pp. 462–468. New York: McGraw-Hill.
  • Gregg EW, et al. (2003). Intentional weight loss and death in overweight and obese U.S. adults 35 years of age and older. JAMA, 138(5): 383–389.
  • Janssen I, et al. (2002). Body mass index, waist circumference, and health risk. Archives of Internal Medicine, 162(18): 2074–2079.
  • Maggard A, et al. (2005). Meta-analysis: Surgical treatment of obesity. Annals of Internal Medicine, 142(7): 547–559.
  • Murray MT, Pizzorno JE Jr (2006). Obesity. In JE Pizzorno Jr, MT Murray, eds., Textbook of Natural Medicine, 3rd ed., vol. 2, pp.1947–1960. St. Louis: Churchill Livingstone.
  • Noël PH, Pugh JA (2002). Management of overweight and obese adults. BMJ, 325(7367): 757–761.
  • Snow V, et al. (2005). Pharmacologic and surgical management of obesity in primary care: A clinical practice guideline from the American College of Physicians. Annals of Internal Medicine, 142(7): 525–531.


Author Jeannette Curtis
Editor Kathleen M. Ariss, MS
Associate Editor Pat Truman, MATC
Primary Medical Reviewer Caroline S. Rhoads, MD - Internal Medicine
Specialist Medical Reviewer Matthew I. Kim, MD - Endocrinology
Last Updated April 16, 2009

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