Health risks of obesity
Obesity is a medical condition in which a high amount of body fat increases the chance of developing medical problems.
People with obesity have a higher chance of developing these health problems:
Obesity
Obesity means having too much body fat. It is not the same as being overweight, which means weighing too much. A person may be overweight from extr...

- High blood glucose (sugar) or diabetes.
- High blood pressure (hypertension).
- High blood cholesterol and triglycerides (dyslipidemia, or high blood fats).
- Heart attacks due to coronary heart disease, heart failure, and stroke.
- Bone and joint problems, more weight puts pressure on the bones and joints. This can lead to osteoarthritis, a disease that causes joint pain and stiffness.
- Stopping breathing during sleep (sleep apnea). This can cause daytime fatigue or sleepiness, poor attention, and problems at work.
- Gallstones and liver problems.
- Some cancers.
Three things can be used to determine if a person's body fat gives them a higher chance of developing obesity-related diseases:
- Body mass index (BMI)
BMI
A good way to decide if your weight is healthy for your height is to figure out your body mass index (BMI). You and your health care provider can us...
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- Other risk factors the person has (a risk factor is anything that increases your chance of getting a disease)

Obesity and health
Obesity increases a person's risk of illness and death due to diabetes, stroke, heart disease, hypertension, high cholesterol, and kidney and gallbladder disease. Obesity may increase the risk for some types of cancer. It is also a risk factor for the development of osteoarthritis and sleep apnea.
Body Mass Index
Experts often rely on BMI to determine if a person is overweight. The BMI estimates your level of body fat based on your height and weight.
Starting at 25.0, the higher your BMI, the greater is your risk of developing obesity-related health problems. These ranges of BMI are used to describe levels of risk:
- Overweight (not obese), if BMI is 25.0 to 29.9
- Class 1 (low-risk) obesity, if BMI is 30.0 to 34.9
- Class 2 (moderate-risk) obesity, if BMI is 35.0 to 39.9
- Class 3 (high-risk) obesity, if BMI is equal to or greater than 40.0
There are many websites with calculators that give your BMI when you enter your weight and height.
Waist Size
Women with a waist size greater than 35 inches (89 centimeters) and men with a waist size greater than 40 inches (102 centimeters) have an increased risk for heart disease and type 2 diabetes. People with "apple-shaped" bodies (waist is bigger than the hips) also have an increased risk for these conditions.
Risk Factors
Having a risk factor for a disease doesn't mean that you will get the disease. But it does increase the chance that you will. Some risk factors, like age, race, or family history can't be changed.
The more risk factors you have, the more likely it is that you will develop the disease or health problem.
Your risk of developing health problems such as heart disease, stroke, and kidney problems increases if you're obese and have these risk factors:
- High blood pressure (hypertension)
- High blood cholesterol or triglycerides
- High blood glucose (sugar), a sign of diabetes
These other risk factors for heart disease and stroke are not caused by obesity:
- Having a family member under the age of 50 with heart disease
- Being physically inactive or having a sedentary lifestyle
- Smoking or using tobacco products of any kind
Summing it up
You can control many of these risk factors by changing your lifestyle. If you have obesity, your health care provider can help you begin a weight-loss program. A starting goal of losing 5% to 10% of your current weight will significantly reduce your risk of developing obesity-related diseases.
Reviewed By
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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