Understanding Adult Overweight and Obesity
When we eat more calories than we burn, our bodies store this extra energy as fat. While a few extra pounds may not seem like a big deal, they can increase your chances of having high blood pressure and high blood sugar. These conditions may lead to serious health problems, including heart disease, stroke, type 2 diabetes, and certain cancers.
Today, more than two-thirds of adults in the United States are considered to be overweight or obese. More than one-third of adults have obesity. This fact sheet will help you find out if you may be at risk of developing weight-related health problems. It will also explain how overweight and obesity are treated and give you ideas for improving your health at any weight.
How can I tell if I am at a normal weight?
Body mass index (BMI) is one way to tell whether you are at a normal weight, overweight, or obese. The BMI measures your weight in relation to your height.
The BMI table below will help you to find your BMI score. Find your height in inches in the left column labeled "Height." Move across the row to your weight. The number at the top of the column is the BMI for that height and weight. Pounds are rounded off. You may also go to the Additional Links section at the end of this page for a link to an online tool for measuring BMI.
A BMI of 18.5 to 24.9 is in the normal range. A person with a BMI of 25 to 29.9 is considered overweight, and someone with a BMI of 30 or greater is considered obese.
However, because BMI doesn't measure actual body fat, a person who is very muscular, like a bodybuilder, may have a high BMI without having a lot of body fat. Please review your findings with your health care provider if your BMI is outside of the normal range.
Table 1. Body Mass Index Table
To use the table, find the appropriate height in the left-hand column labeled Height. Move across to a given weight (in pounds). The number at the top of the column is the BMI at that height and weight. Pounds have been rounded off.
Body Mass Index Table 1 of 2
|Body Weight (pounds)|
Body Mass Index Table 2 of 2
|Body Weight (pounds)|
Why do people gain weight?
Our bodies need calories (energy) to keep us alive and active. But to maintain weight we need to balance the energy we take in with the energy we use. When a person eats and drinks more calories than he or she burns, the energy balance tips toward weight gain, overweight, and obesity. The tipping point at which the calories coming in and the calories going out become out of balance and lead to weight gain may differ from one person to another.
What other factors are involved?
Your genes, the world around you, and other factors may all affect weight gain. Learn how to address these factors in the section "How can I improve my health?"
Research shows that obesity tends to run in families, suggesting that genes may contribute to obesity. Families also share diet and lifestyle habits that may affect weight. However, it is possible to manage your weight even if obesity is common in your family.
The World around You
Where people live, play, and work may also strongly affect their weight. Consider the fact that obesity rates were lower 30 years ago. Since that time, our genetic make-up hasn't changed, but our world has.
The world around us affects access to healthy foods and places to walk and be active in many ways:
- Many people drive rather than walk.
- Living in areas without sidewalks or safe places to exercise may make it tough to be more active.
- Many people eat out or get takeout instead of cooking, which may lead to eating more calories.
- Most vending machines do not offer low-calorie, low-fat snacks.
Overweight and obesity affect people in all income ranges. But people who live in low-income areas may face even greater barriers to eating healthy foods and being active than other people. High-calorie processed foods often cost less than healthier options, such as fruits and vegetables. There also may be few safe, free, or low-cost places nearby to be active on a regular basis. These factors may contribute to weight gain.
A person's culture may also affect weight:
- Some cultures have foods with a lot of fat or sugar, making it hard to manage weight.
- Family events at which people eat large amounts of food may make it tough to control portions.
Research suggests that lack of sleep is linked to overweight and obesity. Recent studies have found that sleeping less may make it harder to lose weight. In these studies, adults who were trying to lose weight and who slept less ate more calories and snacked more.
For more on how obesity and sleep are related, see the Additional Links section at the end of this fact sheet for a link to the WIN fact sheet Do You Know Some of the Health Risks of Being Overweight?
Certain drugs may cause weight gain. Steroids and some drugs to treat depression or other mental health problems may make you burn calories more slowly or feel hungry. Be sure your health care provider knows all the medicines you are taking (including over-the-counter drugs and dietary supplements). He or she may suggest another medicine that has less effect on weight.
Does my body shape matter?
Health care providers are concerned not only with how much body fat a person has, but where the fat is located on the body.
- Women tend to collect fat in their hips and buttocks, giving them a "pear" shape.
- Men usually build up fat around their bellies, giving them more of an "apple" shape.
- Of course, some men are pear-shaped and some women are apple-shaped, especially after menopause.
Extra fat around your midsection may put you at greater risk for type 2 diabetes, heart disease, and other health problems—even if you have a normal weight. Your provider can help you assess your risk.
What problems are linked to excess weight?
Weighing too much may increase the risk for several health problems. It also may contribute to emotional and social problems.
Type 2 diabetes, heart disease, high blood pressure, stroke, kidney disease, and certain cancers are some of the diseases linked to excess weight. Obese men are more likely than other men to develop cancer of the colon, rectum, or prostate. Obese women are more likely than other women to develop cancer of the breast (after menopause), gallbladder, uterus, or cervix. Cancer of the esophagus (the tube that carries food and liquids to the stomach) may also be linked to obesity.
Other diseases and health problems linked to excess weight include
- breathing problems, including sleep apnea
- fatty liver disease (also called nonalcoholic steatohepatitis or NASH)1
- gallbladder disease and gallstones
- pregnancy problems, such as gestational diabetes (high blood sugar during pregnancy), high blood pressure, and increased risk for cesarean section (C-section)
Emotional and Social Effects
Excess weight may also contribute to emotional suffering. Physical beauty and how a person looks are highly valued in society. People who may not fit society's view of beauty because of their weight may be seen as less attractive.
Also, because some people in our culture may view a person with obesity as lacking willpower, people with obesity may face limited options in the job market, at school, and in social situations. They may feel rejected, ashamed, or depressed.
Who should lose weight?
Health care providers generally agree that people who are considered to be obese (have a BMI of 30 or greater) may improve their health by losing weight.
If you are overweight (BMI between 25 and 29.9), experts recommend that you avoid gaining any extra weight. If you are overweight and have other risk factors (see below), losing weight may reduce these risks. Experts recommend you try to lose weight if you have two or more of the following:
- Family history of certain chronic diseases. If you have close relatives who have had diseases such as heart disease or diabetes, you may be more likely to develop these problems.
- Pre-existing medical problems. High blood pressure, high LDL (bad) cholesterol levels, low HDL (good) cholesterol levels, high triglycerides, and high blood sugar (prediabetes or diabetes) are all warning signs of some diseases linked to obesity.
- Large waist size. Men who have waist sizes greater than 40 inches and women who have waist sizes greater than 35 inches are at higher risk of diabetes, unhealthy blood fats (high cholesterol and triglycerides), high blood pressure, and heart disease.
Fortunately, losing even a small amount of weight can help improve your health. This weight loss may lower your blood pressure and improve other risk factors.
For example, research shows that people at high risk for type 2 diabetes who lose a modest amount of weight and increase their physical activity may prevent or delay type 2 diabetes.
How are overweight and obesity treated?
The best way to control your weight may depend on how much excess weight you have, your overall health, and how ready you are to change your eating and physical activity habits. In some cases, if lifestyle changes do not lead to enough weight loss to improve your health, doctors may recommend additional treatment, including weight-loss drugs.
In some cases of extreme obesity, doctors may recommend bariatric surgery. More information about bariatric surgery is provided in the NIDDK health topic, Bariatric Surgery for Severe Obesity.
How can I improve my health?
Although you cannot change your genes, you can work on changing your eating habits, levels of physical activity, and other factors. Try the ideas below.
Get regular physical activity
Try these tips for starting or maintaining an exercise program:
- Get at least 150 minutes (2 ½ hours) of moderately intense aerobic activity each week that raises your heart rate and makes you sweat. Brisk walking, biking (with a helmet), swimming, and playing tennis or basketball are fun choices that you can do with others for support.
- You can spread the 150 minutes out in short spurts over the week. Do house or yard chores briskly, walk the dog at a quick pace, or dance to your favorite music for at least 10 minutes at a time.
- Aim for 300 minutes (5 hours) of aerobic activity a week to prevent gradual weight gain in adulthood. If you are at a healthy weight now but used to be overweight or obese, experts encourage 60 to 90 minutes of exercise a day to keep the weight off.
Most adults don't need to see their doctor before starting a physical activity program. However, those who should see a doctor include men older than 40 and women older than 50 who plan a vigorous program or who have either a serious health condition or risk factors for a serious health condition.
Eating healthy foods has vital health benefits, too, including weight loss. To start eating better, try these tips:
- Eat the rainbow. Make half of what's on your plate fruit and vegetables.
- Replace refined grains with whole grains, like oatmeal, whole wheat bread, and brown rice.
- Get your protein from healthy sources, like seafood, lean meats, poultry, eggs, beans, unsalted nuts, and seeds.
- Instead of sugary drinks, choose unsweetened tea, low-fat milk, or water.
Remember, weight control is a lifelong effort. Starting now with small steps may improve your health. A healthy eating plan and regular physical activity can be steps to a healthier you.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.
What are clinical trials, and are they right for you?
Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.
What clinical trials are open?
Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.
This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.
The NIDDK would like to thank:
Delia Smith West, Ph.D., University of Arkansas for Medical Sciences