Does Diabetes Cause Weight Gain or Does Obesity Cause Diabetes?

The relationship between obesity and diabetes is somewhat complex. Below we’ll explore the relationship between the two, as well as what you can do to improve both conditions, and your overall health. This article will focus solely on type 2 diabetes.

Does Obesity Cause Diabetes?

More than 90% of people with type 2 diabetes also struggle with their weight, and by BMI standards fall into the category of obese. Excess weight increases the chances of developing diabetes, with studies showing that obesity increases the risk of developing diabetes 7-fold in men and 12-fold in women, when compared to persons without excess body weight. However,  body weight is not the only risk factor for developing type 2 diabetes, and not everyone with obesity will develop diabetes. Other risk factors include a family history of diabetes, as well as age, ethnicity, and lifestyle factors such as diet and activity level.

How Does Obesity Cause Diabetes?

Type 2 diabetes is defined by increased blood sugar levels that occur as a result of insulin resistance and decreased insulin secretion. Insulin is a hormone that regulates blood sugar levels by taking sugar out of the bloodstream and delivering it into cells, where it is an important source of energy. Muscle and liver cells play an important role as our bodies store glucose there for later use.

When insulin resistance develops, tissues are less responsive to the action of insulin, so sugar remains in the bloodstream rather than entering cells. The pancreas tries to normalize blood sugar levels by pumping out more insulin, and higher levels of insulin can help compensate for its diminished effect. But the cells of the pancreas in people with insulin resistance struggle to keep up with increasing demands; at some point they cannot keep up. There is then insufficient insulin production to overcome the levels of resistance, and blood sugar levels rise.

Obesity can worsen both insulin resistance and insulin secretion. Many studies link obesity to insulin resistance, and many studies show that in obesity there is dysfunction of the pancreatic cells that produce insulin. So these are fundamental ways in which obesity contributes to rising blood sugar levels and, ultimately, diabetes. 

On the Flipside – Can Diabetes Cause Weight Gain?

When high levels of insulin are secreted to compensate for insulin resistance, it can contribute to weight gain. This is because insulin not only regulates our blood sugar levels, but also promotes fat storage. Insulin resistance and high levels of insulin can lead to increased fat storage and therefore weight gain.

Additionally, treatments used to control blood sugar can themselves contribute to weight gain. Some diabetes medications have weight gain as a side effect, including insulin, as well as other oral medications. Sulfonylureas and thiazolidinediones have weight gain as a potential side effect. These medicines can also increase the risk for low blood sugars, which has to be treated by eating sugar, and therefore can also contribute to increased calories.

For anyone who has a diagnosis of diabetes, it is important to discuss weight as a health issue with your healthcare providers at the time of starting treatment. The good news is that there are diabetes treatment options that do not cause weight gain, and can even help you to lose weight, so a discussion with your healthcare provider about whether those might be appropriate for you can be helpful.

Would Losing Weight Help Manage Your Diabetes?

Losing weight is likely the best thing you can do to manage diabetes. Losing 5-10% of your initial body weight is often recommended for patients with diabetes, but even a 2-5% weight loss has shown meaningful improvements in blood sugar levels. Remission of diabetes has been seen with larger amounts of weight loss (≥ 10-15% of initial body weight), though the ability to achieve this depends on many factors, including how long a person has had diabetes as well as their ability to maintain the weight loss.

Weight loss also improves many of the complications that coexist with diabetes. Studies show that weight loss reduces the need for medications to treat high blood pressure and high cholesterol. It also reduces the risk of damage to the kidneys, eyes, and nerves, which can happen with persistently elevated blood sugar levels.

Is it More Difficult to Lose Weight with Diabetes?

Weight loss is challenging for most people, but research suggests that it could be even harder for people with diabetes. This is likely due to the state of insulin resistance and subsequent fat storage detailed above. There is also the potential for diabetes medications to cause weight gain. Still, there are proven ways to lose weight even for diabetics:

  • Adopt a healthy, reduced-calorie diet. There is no one best diet for losing weight with diabetes. Studies consistently show that reducing calorie intake is the foundation for losing weight. Consuming a nutritionally-balanced diet is important for both weight loss and diabetes management. Try to include non-starchy vegetables daily, and choose whole grain carbs versus refined carbs, and consume primarily lean protein. Try to minimize sugar-sweetened beverages, as well.
  • Increase level of physical activity. This is mutually beneficial for losing weight and improving blood sugar levels. If you’re currently inactive, start slowly by increasing your activity level by 10 minutes per day. Making regular physical activity a part of your life is essential for weight loss maintenance and diabetes management, so find an activity that you enjoy and make it part of your daily routine.
  • Optimize both sleep and stress levels. We focus so much on nutrition and exercise that we forget about the importance of stress management and sleep for losing weight. Both can also play a role in blood sugar regulation and worsen insulin resistance, so making efforts to reduce your stress levels and improve your sleep are important for diabetes management as well.
  • Review your treatment plan with your healthcare provider. If you’re taking medications for diabetes that have weight gain potential or you have noticed that you’re gaining weight after starting on diabetes treatment, it is important to discuss options with your healthcare provider. It is not safe to suddenly stop taking these medications, but there are alternatives that could help you to lose weight while also improving your blood sugar.
  • Seek additional support. If you’re adopting healthier habits but still having difficulty losing weight, it may be time to seek additional help. Registered Dietitians are valuable for patients looking to lose weight and manage diabetes. There are also medical providers who have expertise in treating obesity using tools aimed at addressing biological factors that may be interfering with your success. This may include the use of weight loss medications, some of which can also be beneficial for improving blood sugar levels and therefore help you control diabetes while losing weight.

About the Author: Brooke Marsico, PA-C, completed her physician assistant training at Midwestern University in 2011. She began her practice in the field of Obesity Medicine at Northwestern Memorial Hospital in Chicago where she practiced from 2016 to 2021. She went on to treat patients living with obesity at Cleveland Clinic from 2021 to 2022 prior to joining the team at Form Health. Brooke is passionate about helping patients living with obesity achieve meaningful weight loss and improve their health.

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