How Does Obesity Increase the Risk of Diabetes?

There is a strong link between obesity and type 2 diabetes, and they often occur together. Rates of both of these serious health conditions are increasing. In fact, obesity is now one of the most common noncontagious diseases in the world. Because having both obesity and diabetes is so common, some people refer to it as "diabesity."^1,2

What is obesity?

Obesity is the result of excess fat buildup in the body. In general, when you consume more calories than you are able to burn off, you begin to store fat. If these fat stores reach an unhealthy level, you may be diagnosed with overweight or obesity. Doctors may use body mass index (BMI) or other tests to determine whether your body is storing unhealthy levels of fat.³

What is type 2 diabetes?

Type 2 diabetes occurs when your body cannot regulate blood sugar (glucose) levels. This happens when your body becomes resistant to insulin or has stopped producing enough insulin. Insulin is the main hormone that helps your body use sugar for energy.⁴

Without enough insulin, your blood sugar levels rise too high. Over time, elevated blood sugar can cause serious health problems, for example:⁴

• Heart disease
• Nerve damage
• Vision loss

Can obesity cause diabetes?

Having obesity can change how well many of your organs work. Excess fat can strain most systems in the body, leading to other serious health conditions. Experts have linked more than 50 health conditions to excess body weight.^1,3

One of these conditions is type 2 diabetes. People living with obesity are at high risk for type 2 diabetes. In fact, they are about 6 times more likely to develop diabetes than people who have a healthy body weight. The risk for diabetes in adults increases from less than 12 percent to more than 70 percent when they reach a BMI score considered obese.^2,5

How does obesity lead to diabetes?

Obesity and type 2 diabetes are linked in several complex ways. But the main way obesity can lead to diabetes is by causing insulin resistance. Insulin resistance happens when your cells do not respond well to insulin. This makes it harder for your body to keep blood sugar levels in balance.^1,2

Here is how it works: Your pancreas makes insulin. Insulin is responsible for moving blood sugar into muscle cells for energy. Insulin also moves extra blood sugar into the liver to be stored for later use. But when there are a large number of fat cells in the body, those cells trigger inflammation that interferes with this process.^1,2

Your muscle cells and liver stop being able to accept and use blood sugar. So, your pancreas goes into overdrive. It makes more insulin so the muscles can get the energy they need. But eventually, your pancreas cannot make enough insulin. Sugar builds up in your blood, causing high blood sugar (hyperglycemia).^1,2

Over time, hyperglycemia can lead to diabetes. It also can lead to more weight gain. This can further the vicious cycle of obesity and type 2 diabetes.^1,2

Are there other reasons for the connection?

The harmful effect of obesity on the body is not the only link between obesity and diabetes. The 2 conditions also share some shared genetic and environmental risk factors, including the following.^1,3,4,6-11

Family history

Having immediate family members with diabetes increases your risk for the condition. The same is true for obesity.^1,3,4,6-11

Genes

Experts have linked at least 250 genes to obesity and 150 gene changes to type 2 diabetes. For example, people who have changes to genes that control hunger signals may have trouble knowing when they are full. Genetic changes can be passed down through your family. Or they can occur in response to things in your environment.^1,3,4,6-11

Maternal health

The health of pregnant people can strongly affect the future health of their babies. For example, the child of a mother who had diabetes during pregnancy is more likely to develop diabetes and/or obesity. And the child of a mother who smoked during pregnancy is more likely to develop obesity.^1,3,4,6-11

Unhealthy diet

Consuming too many calories or calories from unhealthy foods can put you at greater risk for obesity. An unhealthy diet also can lead to blood sugar imbalances, resulting in diabetes. Even poor nutrition only in early childhood can increase your risk for obesity and diabetes in adulthood.^1,3,4,6-11

Inactive lifestyle

Not getting enough exercise increases your risk of diabetes. Physical activity helps your body use insulin more efficiently. Exercise also helps you burn the calories you take in through food and drink.^1,3,4,6-11

Poor sleep

Sleeping too little or poor sleep quality may increase your risk for both obesity and type 2 diabetes.^1,3,4,6-11

High stress levels

In times of high stress, your body releases stress hormones. Research suggests that these hormones can make the pancreas less able to produce insulin. They also may make the body less able to use existing insulin. Type 2 diabetes can result from these changes. Stress hormones also can increase appetite and food cravings. This might lead to overeating, a factor in obesity.^1,3,4,6-11

Gut health

Frequent use of antibiotics in childhood or adulthood can change the balance of microorganisms, or microbes, in your gut. Some of these changes have been linked to obesity. Other research has linked specific microbes in the gut to higher risk for type 2 diabetes.^1,3,4,6-11

How can diabesity be treated?

Researchers are still discovering ways that obesity and type 2 diabetes may be linked. But they know that the best way to prevent and treat both conditions is by reaching a healthy body weight. Losing 5 to 10 percent of your body weight can significantly improve insulin resistance.^2,5

Reaching a healthy body weight can be accomplished in a number of different ways:^1,2,5

• Diet and lifestyle changes
• Weight loss medicine
• Weight loss surgery
• Making adjustments to any current drugs you are taking that may be leading to weight gain

Your doctor will help you understand the best weight-loss methods for you. Often, the first step is to make lifestyle changes that will increase your overall health. These changes may include:^1,5

• Eating a healthy, balanced diet
• Exercising more regularly
• Getting more and better-quality sleep by creating consistent sleep habits
• Managing stress levels through stress-reduction techniques like meditation or yoga