Being overweight or obese increases your risk for diabetes. But if you already have diabetes, being overweight makes it harder to manage your diabetes, and increases your risk for high cholesterol, high blood pressure and cardiovascular disease (the major cause of death among people with diabetes).

How do I know if I am overweight or obese?
Your body is made up of water, fat, protein, carbohydrates and various vitamins and minerals. If you have too much fat — especially in your waist area — you're at higher risk for high blood pressure, high blood cholesterol, diabetes, heart disease and stroke.

Waist circumference measurement and body mass index (BMI) are the recommended ways to estimate body fat. A high-risk waistline is more than 35 inches for women, more than 40 inches for men.

The body mass index formula assesses body weight relative to height. It's an indirect measure of body composition, because in most people it correlates highly with body fat. Weight in kilograms is divided by height in meters squared (kg/m²). Or multiply weight in pounds by 703, divide by height in inches, then divide again by height in inches. In studies by the National Center for Health Statistics:

• BMI values less than 18.5 are underweight.
• BMI values from 18.5 to 24.9 are normal.
• Overweight is defined as a body mass index of 25.0 to 29.9 (consistent with U.S. dietary guidelines for Americans). A BMI of about 25 kg/m² corresponds to about 10 percent over ideal body weight.
• Obesity is defined as a BMI of 30.0 or greater (consistent with criteria of the World Health Organization), or about 30 pounds or more overweight. Extreme obesity is defined as a BMI of 40 or greater.

Why should I lose weight?
Even moderate weight loss improves glycemic control (blood glucose control), can help reduce blood pressure and cholesterol, reduces risk for cardiovascular disease, and can even help prevent diabetes in people with prediabetes.

How do I lose weight?
The first step is to talk to your doctor. Based on your health and current abilities, he or she will recommend modest lifestyle changes related to diet and physical activity. Physical activity is an important part of losing weight. It also improves insulin sensitivity and glycemic control. The amount of activity you begin with is up to you and your doctor, but the duration and frequency should generally increase to at least 30 to 45 minutes of moderate aerobic activity at least three to five times a week, or more. Greater levels may be required to achieve long-term weight loss.

This content is reviewed regularly. Last updated 09/05/08.