Give Online: Help shape patient care for generations to come.
Cleveland Clinic Logo

Diseases & Conditions

Questions About Weight Control and Obesity

Health & Wellness Programs

Did you know Cleveland Clinic offers nutrition, fitness and educational programs that can help you live a healthy lifestyle?

Learn more

Print these questions and answers to discuss with your healthcare provider.

What causes obesity?

In scientific terms, obesity occurs when a person's calorie intake exceeds the amount of energy he or she burns. What causes this imbalance between consuming and burning calories is unclear. Evidence suggests that obesity often has more than one cause. Environmental, psychological, genetic, and other factors all may play a part.

Environmental factors: A person's environment plays a significant role in weight status. Environment includes lifestyle behaviors, such as what a person eats and how active he or she is. Americans tend to have high-fat diets, often putting taste and convenience ahead of nutritional content when choosing meals. People can change what they eat and how active they are as a means of changing their weight status.

Psychological factors: Psychological factors also may influence eating habits. Many people eat in response to negative emotions such as boredom, sadness, or anger.

About 30% of those who seek treatment for serious weight problems have difficulties with binge eating. During a binge eating episode, people eat large amounts of food while feeling they can't control how much they are eating. Those with the most severe binge eating problems are considered to have what is called binge eating disorder. These people may have more difficulty losing weight and keeping the weight off than people without binge eating problems. Some will need special help, such as counseling or medication, to control their binge eating before they can successfully manage their weight.

Genetic factors: Obesity tends to run in families, suggesting that it may have a genetic cause. However, family members share not only genes but also diet and lifestyle habits that may contribute to obesity. Separating these lifestyle factors from genetic ones is often difficult. Still, growing evidence points to heredity as a strong determining factor of obesity. In one study of adults who were adopted as children, researchers found that their subjects' adult weights were closer to their biological parents' weights than their adoptive parents'. The environment provided by the adoptive family apparently had less influence on the development of obesity than the person's genetic makeup. However, many people genetically predisposed to obesity do not become obese or are able to lose weight and keep it off.

Other causes of obesity: Some illnesses can lower the metabolism or trigger an increased appetite which can cause obesity. These include hypothyroidism, Cushing's syndrome, depression, and certain neurologic problems. Certain drugs, such as steroids and some antidepressants, may cause excessive weight gain through the same methods. A doctor can determine if a patient has any of these conditions, which are believed to be responsible for only about 1% of all cases of obesity.

Can being overweight lead to medical problems?

Yes. Being overweight is linked to a number of health problems, including:

Obesity is not just a cosmetic problem. It is a health hazard. Someone who is 40% overweight is twice as likely to die prematurely as an average-weight person. (This effect is seen after 10 to 30 years of being obese.)

Doctors generally agree that the more obese a person is, the more likely it is that he or she will have health problems. People who are 20% or more overweight can gain significant health benefits from weight loss. Many obesity experts believe that people who are less than 20% above their healthy weight should try to lose weight if they have any of the following risk factors.

  • Family history of certain chronic diseases: People with close relatives who have had heart disease or diabetes are more likely to develop these problems if they are obese.
  • Pre-existing medical conditions: High blood pressure, high cholesterol levels, or high blood sugar levels are all warning signs of some obesity-associated diseases.
  • "Apple" shape: People whose weight is concentrated around the abdomen may be at greater risk of developing heart disease, diabetes, or cancer than people of the same weight who are "pear-shaped."

Fortunately, even a modest weight loss of 10 to 20 pounds can bring significant health improvements, such as lower blood pressure and cholesterol levels.

How do I know if I am obese?

Obesity is defined as an excess proportion of total body fat. Speak with your doctor if you are concerned about your weight and if you are attempting weight loss. You should call your doctor if you need help in losing weight or if you fall into either of these categories:

  • Body mass index (BMI): If your BMI is 30 or greater, you're considered obese and should talk to your doctor about losing weight for your health.
  • Waist circumference: If you have an "apple shape" — a "potbelly" or "spare tire" — you carry more fat in and around your abdominal organs. Fat in your abdomen increases your risk of many of the serious conditions associated with obesity. Women's waist measurement should fall below 35 inches. Men's should be less than 40 inches. If you have a large waist circumference, talk to your doctor about weight loss.

How is obesity treated?

The treatment of obesity needs to be long-term; it cannot be short-term. Weight loss should be gradual, and careful follow-up is necessary to prevent rebound weight gain. Changing behavior and lifestyle are the only ways to change a person's weight permanently. These changes focus on gradual and permanent changes in eating and exercise habits. There are six ways you can change your behavior and lifestyle that will help you maintain weight loss:

  • Learning about nutrition
  • Changing your eating habits
  • Increasing your physical activity
  • Changing your attitudes about eating
  • Joining a weight loss program
  • Developing support systems
  • Following any drug therapies ordered by your doctor

The keys to weight management include making lifestyle changes, such as increasing exercise and activity and changing dietary habits.

What about prescription weight loss medications?

Prescription drugs are another approach to treating obesity. Drug therapy may help the patient learn and adapt to a healthier lifestyle. It should be used along with a program of diet and exercise and should help you follow your overall treatment plan.

The anti-obesity medications that are currently available work mainly by suppressing the appetite. They raise specific hormones such as noradrenalin or serotonin in the nervous system, creating a feeling of fullness. These medications will not work, however, unless you also make changes in your diet and lifestyle.

The level of success with anti-obesity drugs is rather modest. Studies show a mean weight loss of six to 10 pounds total and about one-half pound a week greater weight loss than with a placebo (for 12 weeks or less of treatment). Some individuals respond very well while others may not respond at all.

A weight loss medication is not a cure-all. The use of weight loss medications should be combined with physical activity and improved diet to lose and maintain weight successfully over the long term.

Weight loss medications can be considered for:

  • People with a BMI greater than 30 with no obesity-related conditions
  • People with a BMI of greater than 27 with two or more obesity-related conditions

Currently, most available weight-loss medications approved by the FDA are for short-term use, meaning a few weeks or months.

What about weight loss surgery?

Another treatment option may be surgery. Surgery should only be considered after all other attempts to lose weight have been unsuccessful, or if a person has an obesity-related disease. Surgery should only be done at centers committed to long-term follow-up and as an addition to diet, exercise, and behavior modification programs. Currently, candidates for these surgeries have to be:

  • Severely obese (A BMI greater than 35)
  • Well-informed
  • Assessed by dietician, psychologist, endocrinologist, and other specialists before being considered for the procedure

Surgical procedures have had the most long-term success, but it is important to consider the reasons for success or failure of previous weight-loss attempts as well as the risks and benefits of the surgery.

How much exercise should I do?

Studies show that even the most inactive people can gain significant health benefits if they accumulate just 30 minutes or more of physical activity per day.

For the greatest overall health benefits, experts suggest 30 minutes of moderate-intensity aerobic exercise three or more times per week, plus some form of anaerobic exercise, such as muscle-strengthening activity and stretching twice a week.

If you have been inactive for a while, you may want to start with less strenuous activities, such as walking or swimming at a comfortable pace. Beginning at a slow pace will allow you to become physically fit without straining your body. Once you are in better shape, you can gradually do more strenuous activity.

How do I spot a fad diet?

Fad diets typically do not support long-lasting weight loss results. Avoid fad diets, and focus instead of portion control, cutting down on empty calories like sweets and sugary drinks, and increasing exercise. While there is no set approach to identifying a fad diet, many have the following characteristics:

  • Recommendations that promise a quick fix
  • Dire warnings of dangers from a single product or regimen
  • Claims that sound too good to be true
  • Simplistic conclusions drawn from a complex study
  • Recommendations based on a single study
  • Dramatic statements that are refuted by reputable scientific organizations
  • Lists of "good" and "bad" foods
  • Recommendations made to help sell a product
  • Recommendations based on studies published without review by other researchers
  • Recommendations from studies that ignore differences among individuals or groups
  • Elimination of one or more of the five food groups

How can I lose weight and then prevent gaining it back?

Keep the following tips in mind.

  • Set realistic weight loss goals, such as a one- to two-pound weight loss per week. Those who lose weight slowly, by eating less and exercising more, tend to keep their lost weight off. Even a half pound weight loss per week would result in a 25-pound loss over one year.
  • Eat fewer calories by cutting down on portion sizes. An easy way to portion a plate is to put fruits and vegetables on half, starch on one quarter of the plate, and protein on the other quarter of the plate.
  • Aim for at least five handfuls of fruits and vegetables per day.
  • Do not skip meals. This slows down metabolism and can lead to increased hunger and binging. Four to five “mini-meals” regularly spaced throughout the day may help satisfy your hunger while keeping your weight under control.
  • Feel free to include planned, healthy snacks between meals if you find you struggle with physical hunger during the day. Some examples would be fat-free Greek yogurt, cottage cheese and fruit, vegetables and hummus, string cheese and fresh fruit, or a palm full of nuts.
  • Choose foods high in fiber, such as whole grain breads, cereals, pasta, rice, fruits, and vegetables. These foods will give you more chewing satisfaction, while the higher fiber content may make you feel fuller on fewer calories.
  • To ensure that you are eating healthy, keep an accurate food journal. Write down everything you eat or drink. Be honest and accurate, otherwise the journal is not as helpful. The food journal will help you learn about your eating habits and help you assess the food choices you are making.
  • Eat a variety of foods. Include all food groups to get all the nutrients you need.
  • Limit restaurant foods.
  • Plan ahead: plan meals for the week, create a grocery list, and keep healthy foods available to you in your kitchen and pantry. Keep trigger foods out of the house and office.

© Copyright 1995-2016 The Cleveland Clinic Foundation. All rights reserved.

Can't find the health information you’re looking for?

This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 4/26/2016...#11209