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About obesity

Overweight and obesity are increasingly common conditions in the United States. Almost 70% of adults in the United States are overweight. And of those, about one third are considered obese. Obesity is a serious chronic illness that can lead to type 2 diabetes, heart disease — two of the leading causes of kidney disease — as well as high blood cholesterol, cancers, and sleep disorders.

Being overweight or obese are both terms for having more body fat than what is considered healthy. These terms are used to identify people who are at risk for health problems from having too much body fat. However, the term "obese" generally means a much higher amount of body fat than "overweight."

Everyone needs some body fat for energy, heat insulation, and other body functions. But having too much can lead to serious health problems. The more body fat you have, the greater your risk for diabetes, kidney disease, heart disease, and other medical conditions.


Signs and symptoms

There are no specific symptoms of overweight and obesity. The signs of overweight and obesity include a high body mass index (BMI), which is calculated from your height and weight. To find your BMI, multiply your weight in pounds by 704.5. Then, divide the result by your height in inches and divide that result by your height in inches a second time. Another sign of obesity is unhealthy body fat distribution that can be estimated by measuring your waist circumference.

It is important to note, however, that BMI estimates body fat. It does not directly measure body fat. As a result, some people with muscular builds, such as athletes, may have a BMI that falls into the overweight range even though they do not have excess body fat.

  • Body mass index (BMI) is used to determine if you underweight, healthy, or overweight or obese. If your BMI is:
    • Less than 18.5 - underweight range
    • Over 18.5 and under 25 - healthy weight range
    • Over 25.0 and under 30 - overweight range
    • Over 30.0 - obesity range
  • Unhealthy body fat distribution occurs when a person has too much fatty tissue, specifically, high amounts of fat in the abdomen, causing increased weight around the waist. If your excess weight is mostly around your middle (apple shape), you are more likely to develop health problems than if the weight is around your hips (pear shape).

BMI Chart

BMI Category
Lower than 18.5 Underweight
18.5 up to 25 Healthy
25 up to 30 Overweight
Greater than 30 Obese


Obesity is a complex health issue resulting from a combination of causes, including environmental and social factors as well as personal behaviors and family history. Personal behaviors can include physical activity and inactivity, dietary patterns, and alcohol and drug use. Additional contributing factors include having access to healthy foods, your physical environment, education, employment and more.

Personal behaviors

Lack of physical activity, unhealthy eating patterns, not enough sleep, and high amounts of stress can increase your risk for overweight and obesity.

  • Lack of physical activity: TVs, computer monitors, video games, and other screen usage has been associated with a high BMI. Healthy lifestyle changes, such as being physically active and reducing screen time, can help you to achieve a healthy weight.
  • Unhealthy eating behaviors: Eating more calories than you use, too much saturated and trans fats and foods high in added sugars can contribute to weight gain and lead to overweight and obesity.
  • Not enough sleep: Some studies have seen a relationship between sleep and the way our bodies use nutrients for energy and how lack of sleep can affect hormones that control hunger urges.
  • High amounts of stress: The effect of stress on the brain, triggers the production of hormones, such as cortisol, that control our energy balances and hunger urges. Acute stress can trigger hormone changes that make you not want to eat. If the stress becomes chronic, hormone changes can make you eat more and store more fat.

Community and environment

People and families may make decisions based on their environment or community. For example, a person may not walk or bike to the store or to work because of a lack of sidewalks or safe bike trails. Community, home, childcare, school, health care, and workplace settings can all influence daily behaviors, which is why it's important to create environments that make it easier to engage in physical activity and eat healthy foods. These factors can increase your risk for overweight and obesity:

  • Environment factors such as an abundance of unhealthy fast food restaurants, limited access to recreational facilities or parks, and few safe sidewalks in your neighborhood
  • Exposure to chemicals known as obesogens that can change hormones and increase fatty tissue in our bodies

Genetics and family history

Genes give the body instructions for responding to changes in its environment. Variants in several genes may contribute to obesity by increasing hunger and food intake. Rarely, a clear pattern of inherited obesity within a family is caused by a specific variant of a single gene. Most obesity, however, results from complex interactions among multiple genes, social and environmental factors, and personal behaviors.

Family health history reflects the effects of shared genetics and environment among close relatives. Families cannot change their genes, but they can choose healthy eating habits and physical activity. Those changes can improve the health of family members—and improve the health history of the next generation of family. Children whose parents eat high-calorie foods and are inactive tend to learn these same habits.

Diseases and drugs

Some illnesses may lead to obesity or weight gain. These may include Cushing’s disease and polycystic ovary syndrome. Drugs such as steroids and some antipsychotics, antidepressants, antiepileptics, and antihyperglycemics may also cause weight gain and can also lead to overweight and obesity.


Being overweight or having obesity may raise your risk for some health problems and may be linked to certain emotional and social problems.

Type 2 diabetes

Type 2 diabetes is a disease that occurs when your blood glucose, also called blood sugar, is too high. About 8 out of 10 people with type 2 diabetes are overweight or have obesity. Over time, high blood glucose leads to problems such as heart disease, stroke, kidney disease, eye problems, nerve damage, and other health problems.

If you are at risk for type 2 diabetes, losing 5% to 7% of your body weight and getting regular physical activity may prevent or delay the onset of type 2 diabetes.

High blood pressure

High blood pressure, also called hypertension, is a condition in which blood flows through your blood vessels with a force greater than normal. High blood pressure can strain your heart, damage blood vessels, and raise your risk of heart attack, stroke, kidney disease, and death.

Heart disease

Heart disease is a term used to describe several problems that may affect your heart. If you have heart disease, you may have a heart attack, heart failure, sudden cardiac death, angina, or an abnormal heart rhythm. High blood pressure, abnormal levels of blood fats, and high blood glucose levels may raise your risk for heart disease. Blood fats, also called blood lipids, include HDL cholesterol, LDL cholesterol, and triglycerides.

Losing 5% to 10% of your weight may lower your risk factors for developing heart disease. If you weigh 200 pounds, this means losing as little as 10 pounds. Weight loss may also improve blood pressure, cholesterol levels, and blood flow.


Stroke is a condition in which the blood supply to your brain is suddenly cut off and is usually caused by a blockage or the bursting of a blood vessel in your brain or neck. A stroke can damage brain tissue and make you unable to speak or move parts of your body. High blood pressure is the leading cause of strokes.

Sleep Apnea

Sleep apnea is a common disorder in which you do not breathe regularly while sleeping. You may stop breathing altogether for short periods of time. Untreated sleep apnea may raise your risk of other health problems, such as type 2 diabetes and heart disease.

Metabolic syndrome

Metabolic syndrome is a group of conditions that put you at risk for heart disease, diabetes, and stroke. These conditions include:

  • High blood pressure
  • High blood glucose levels
  • High triglyceride levels in your blood
  • Low levels of HDL cholesterol (the “good” cholesterol) in your blood
  • Excess fat around your waist

Fatty liver diseases

Fatty liver diseases are conditions in which fat builds up in your liver. Fatty liver diseases include nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Fatty liver diseases may lead to severe liver damage, cirrhosis, or even liver failure.


Osteoarthritis is a common, long-lasting health problem that causes pain, swelling, and reduced motion in your joints. Being overweight or having obesity may raise your risk of getting osteoarthritis by putting extra pressure on your joints and cartilage.

Gallbladder disease

Overweight and obesity may raise your risk of getting gallbladder diseases, such as gallstones and cholecystitis. Imbalances in substances that make up bile cause gallstones. Gallstones may form if bile contains too much cholesterol.

Some cancers

Cancer is a collection of related diseases. In all types of cancer, some of the body’s cells begin to divide without stopping and spread into surrounding tissues. Overweight and obesity may raise your risk of developing certain types of cancer.

Kidney disease

Kidney disease occurs when your kidneys are damaged and can’t filter blood like they should. Obesity raises the risk of diabetes and high blood pressure, the most common causes of kidney disease. Even if you don’t have diabetes or high blood pressure, obesity itself may lead to developing kidney disease and quicken its progress.

Pregnancy problems

Overweight and obesity raise the risk of health problems that may occur during pregnancy. Pregnant women who are overweight or obese may have a greater chance of developing gestational diabetes and having preeclampsia, which is a kind of high blood pressure that occurs during pregnancy. Preeclampsia can cause severe health problems for mother and baby if left untreated. Pregnant women with preeclampsia may need to have a cesarean section (C-section) and, as a result, may take longer to recover after giving birth.

Emotional and social problems

Overweight and obesity are associated with mental health problems such as depression. People who are overweight or obese may also be the subject of weight bias and stigma from others, including health care providers. This can lead to feelings of rejection, shame, or guilt—further worsening mental health problems.



Doctors calculate BMI and measure waist circumference to screen and diagnose overweight and obesity.



Common treatments for overweight and obesity include losing weight through healthy eating, being more physically active, and making other changes to your usual habits. Weight-management programs may help some people lose weight or keep from regaining lost weight. Some people who have obesity are unable to lose enough weight to improve their health or are unable to keep from regaining weight. In such cases, a doctor may consider adding other treatments, including weight-loss medication, weight-loss devices, and/or bariatric surgery.

Experts recommend losing 5% to 10% of your body weight within the first 6 months of treatment. If you weigh 200 pounds, this means losing as little as 10 pounds. Losing 5% to 10% percent of your weight may:

  • Help lower your chances of developing health problems related to overweight and obesity
  • Improve health problems related to overweight and obesity, such as high blood pressure and high cholesterol levels

Healthy eating plan and regular physical activity

Following a healthy eating plan with fewer calories is often the first step in trying to treat overweight and obesity. People who are overweight or have obesity should also start regular physical activity when they begin their healthy eating plan. Being active may help you use calories. Regular physical activity may help you stay at a healthy weight.

Changing your habits

Changing your eating and physical activity habits and lifestyle may be difficult, but with a plan, effort, regular support, and patience, you may be able to lose weight and improve your health. The following tips may help you think about ways to lose weight, engage in regular physical activity, and improve health over the long-term.

  • Be prepared for setbacks—they are normal: After a setback, like overeating at a family or workplace gathering, try to regroup and focus on getting back to your healthy eating plan as soon as you can. Try to eat only when you’re sitting at your dining room or kitchen table. At work, avoid areas where treats may be available. Track your progress using online food or physical activity trackers, that can help you keep track of the foods you eat, your physical activity, and your weight. These tools may help you stick with it and stay motivated.
  • Set goals: Having specific goals can help you stay on track. Rather than “be more active,” set a goal to walk 15 to 30 minutes before work or at lunch on Monday and Friday. If you miss a walk on Monday, pick it up again Tuesday.
  • Seek support: Ask for help or encouragement from your family, friends, or health care professionals. You can get support in person, through email or texting, or by talking on the phone. You can also join a support group. Specially trained health professionals can help you change your lifestyle.

Weight-management programs

Some people benefit from a formal weight-management program. In a weight-management program, trained specialists will design a broad plan just for you and help you carry out your plan. Plans include a lower-calorie diet, increased physical activity, and ways to help you change your habits and stick with them. You may work with the specialists on-site (that is, face-to-face) in individual or group sessions. The specialists may contact you regularly by telephone or internet to help support your plan. Devices such as smartphones, pedometers, and accelerometers may help you track how well you are sticking with your plan.

Some people may also benefit from online weight-management programs or commercial weight-loss programs.


When healthy eating and physical activity habits are not enough, your doctor may prescribe medicines to treat overweight and obesity. Before prescribing medicine or recommending devices or surgery, most doctors will request their patients demonstrate healthy lifestyles that include better nutrition and increased physical activity. Even after prescription medicine, devices or surgical treatments, patients will need to maintain a healthy lifestyle for the rest of their lives. Despite treatments and lifestyle changes, some patients may not be able to lose weight or maintain weight loss.

You may see ads for herbal remedies and dietary supplements that claim to help you lose weight. Most of these claims are not true. Some of these supplements can even have serious side effects. Talk with your doctor before taking any over-the-counter herbal remedies or dietary supplements for the purpose of trying to lose weight.

Weight-loss and -management devices

Your doctor may consider weight-loss devices if you haven’t been able to lose weight or keep from gaining back any weight you lost with other treatments. Because weight-loss devices have only recently been approved, researchers do not have long-term data on their safety and effectiveness. The FDA categorizes devices as weight-loss or weight-management devices based on the amount of weight a person is expected to lose.

For some weight-loss devices, patients should be evaluated and treated for eating disorders before considering using the device as part of their obesity treatment. An undiagnosed and untreated eating disorder can have serious health consequences for patients. Some devices are not for patients that have a history of eating disorders. Medical professionals may also find it appropriate to closely monitor patients with certain weight-loss devices during treatment for evidence of an eating disorder.

Weight-loss Devices

Currently, there are 3 approved devices intended for weight-loss:

  • Gastric Band: Bands are placed around the top portion of the stomach leaving only a small portion available for food.
  • Gastric Balloon Systems: Inflatable balloons are placed in the stomach to take up space and delay gastric emptying.
  • Gastric Emptying Systems: A tube is inserted between the stomach and outside of abdomen to drain food into the toilet after eating.

Weight-management devices

Currently, there are 2 approved devices intended to aid with weight management:

  • Oral Removable Palatal Space Occupying Device: A device worn in the mouth while eating to limit bite size.
  • Ingested, Transient, Space Occupying Device: An ingested material that occupies space in the stomach for a short time

Bariatric surgery

Bariatric surgery includes several types of operations that help you lose weight by making changes to your digestive system. Bariatric surgery may be an option if you have extreme obesity and haven’t been able to lose enough weight to improve your health or keep from gaining back the weight you lost with other treatments. Bariatric surgery also may be an option at lower levels of obesity if you have additional serious health problems, such as type 2 diabetes or sleep apnea, related to obesity. Bariatric surgery can improve many of the medical conditions linked to obesity, especially type 2 diabetes.


Many people don't realize that a lot of people who are overweight and obese are also malnourished. Malnutrition is defined as poor nutrition due to inadequate or unbalanced intake of nutrients. It's commonly thought that malnutrition only affects those who are underweight. Malnutrition is largely under-recognized and often not treated in patients with high BMI. And unhealthy body fat distribution, especially abdominal fat, is often mistaken to by caused by overnutrition rather than undernutrition. In fact, the World Health Organization reports that malnutrition affects more than 4 times more overweight or obese individuals than those who are underweight. The reason why malnutrition is high in overweight and obese people is often due to having an unhealthy diet -- one that's typically high in calories and salt but has few healthy nutrients, such as sugary carbonated drinks or fast foods. These foods are also empty-calorie foods.

Fewer than 1 in 10 adults eat the recommended daily amount of fruits and vegetables. Some people don’t have the information they need to choose healthy foods. Other people don’t have access to healthy foods or can’t afford to buy enough food that is nutrient-rich. Many people in the United States live in neighborhoods that do not have access to healthy food retailers. The availability of healthy, affordable foods can make it easier for people to choose healthier options.

Where people eat also appears to influence their food decisions. For example, foods eaten away from home often have more calories and are of lower nutritional quality than foods prepared at home.

fast food icon

A "food swamp" is an area where an abundance of fast food, junk food outlets, convenience stores, and liquor stores outnumber healthy food options. It’s distinct from a "food desert," which is a neighborhood with little access to affordable, nutritious food.


Only 1 in 4 adults in the United States meet physical activity guidelines for aerobic and muscle-strengthening activities. Physical activity can help prevent disease, disability, injury, and premature death. Although most people don’t get the recommended amount of physical activity, it can be especially hard for older adults and people with chronic diseases or disabilities. Yet not everyone has access to convenient, affordable and safe places to be physically active.

To lose weight and keep it off, you will need a high amount of physical activity unless you also adjust your diet and reduce the amount of calories you’re eating and drinking. Getting to and staying at a healthy weight requires both regular physical activity and a healthy eating plan.

Preparing for your appointment

Questions for your doctor

You and your healthcare provider will need to work together to make treatment choices that are best for you. Here are some questions to help you begin a discussion. It is helpful to write your questions down before your appointments, and bring the list with you. Doing so will help you make the best use of your time together.

  • What is my BMI?
  • Do I have unhealthy body fat distribution?
  • Am I overweight or obese?
  • Am I malnourished?
  • What kind of a diet should I follow?
  • What kind of physical activities should I do?
  • What are my treatment options?
  • Will losing weight help any of my chronic conditions? Which ones?
  • Are there any clinical trials I should think about?


National Kidney and Urologic Disease Information Clearinghouse (NKUDIC), a service of the National Institute of Diabetes, Digestive and Kidney Diseases.
800.891.5390 or

Centers for Disease Control and Prevention:

Malnutrition in the Obese: Commonly Overlooked But With Serious Consequences:

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