Obesity and diabetes: What's the connection?

Obesity is linked with a higher risk of many health conditions, such as heart disease, stroke and type 2 diabetes. In fact, over 85% of people with diabetes are overweight or have obesity.

Obesity is not a direct cause of diabetes. However, obesity — defined as having a body mass index (BMI) of 30 or greater — is a risk factor for type 2 diabetes. Carrying excess weight can make your body’s cells become less resistant to insulin, a hormone that’s needed to help move glucose (sugar) from the blood to the cells. Without enough insulin, glucose builds up in the bloodstream, causing high blood sugar levels. Type 2 diabetes occurs when the body loses its ability to use insulin properly (insulin resistance) or it doesn’t make enough insulin.

Note that a risk factor is something that increases your chance of developing a disease, but it doesn’t necessarily cause it. Even though obesity is related to type 2 diabetes, you are not destined to get diabetes just because you have obesity. Rather, you have a higher risk of developing diabetes compared to people who do not have obesity.

Having obesity increases the risk of type 2 diabetes.

Take heart in knowing that you can take action to lower your risk of diabetes, even if you have a lot of weight to lose. A modest weight loss of 3% to 7% of your current body weight — that's 6 to 14 lbs. if you weigh 200 lbs. — can help prevent or delay type 2 diabetes. Studies have shown that a weight loss greater than 10% of body weight usually produces greater benefits to your health if you have obesity. In general, to lose weight, you need to move more and eat less.

• Get regular exercise. Physical activity can help you shed pounds. It can also decrease insulin resistance and blood sugar levels. Check with your healthcare provider before you start an exercise program. Then, slowly increase your activity level. Work up to five, 30-minute fitness sessions each week.
• Choose nutritious foods. Limit foods and beverages high in saturated and trans fats, sodium and added sugars. Replace less healthy foods in your diet with fruits, vegetables, lean sources of protein, whole grains and  
  low-fat or nonfat dairy products.
• Keep portion sizes in check. Read food labels closely to make sure you aren’t eating more than one serving at a time. Try eating off a smaller plate and skip second helpings.

If you have diabetes and obesity, your weight can make managing diabetes more challenging. However, reducing your weight can have a positive effect on your diabetes. Studies show that losing a moderate amount of weight and keeping it off can improve blood sugar control and possibly reduce the need for diabetes medications.

Making small changes today can set you up for a healthier future. If you’re having trouble losing weight, reach out to your healthcare provider. They may recommend you work with a registered dietitian, suggest counseling or behavioral management, take certain medications, or they may refer you to a weight loss program. Together, you can create a realistic plan that can help you meet your weight loss goals.

Clinically reviewed and updated by Julie McDaniel, MSN, RN, CRNI, March 2024.