Insulin therapy, a common treatment for diabetes, can cause people to gain weight. Certain diet and lifestyle strategies can help people taking this treatment to manage their weight.

There is a well-established link between diabetes and obesity.

Young adults with type 1 diabetes have a higher likelihood of developing excess body weight or obesity than people who do not have diabetes, for example. And at least 85% of people with type 2 diabetes are either overweight or have obesity.

People with diabetes may also gain weight as a side effect of insulin therapy. This treatment helps manage blood sugar, or “glucose,” levels. But the body can store excess glucose as fat.

In this article, we look into the relationship between diabetes, insulin therapy, and weight gain. We also explore ways to avoid insulin-related weight gain.

Insulin is a hormone that regulates levels of glucose in the blood. Another name for “glucose” is blood sugar. The hormone helps cells absorb glucose.

During digestion, insulin stimulates muscle, fat, and liver cells to absorb glucose. The cells either use this glucose for energy or convert it into fat for long-term storage.

If a person has type 1 diabetes, their body does not make enough insulin. If a person has type 2 diabetes, their pancreas makes enough insulin, but the cells do not use it efficiently. The pancreas then responds by making more and more insulin. This is called insulin resistance.

Eating more carbohydrates than the body can process can result in high blood glucose levels. This is because the body breaks down carbohydrates into simple sugars. If the cells do not effectively remove glucose from the blood, the body stores the glucose in tissues as fat. This can cause weight gain.

Reducing excess body weight can help people manage diabetes — and even reverse prediabetes and insulin resistance.

When a person takes insulin as a treatment for diabetes, they may gain weight. This is because their body begins absorbing glucose again and converting any excess into fat.

If treatment does not manage diabetes well, and blood glucose levels are too high, this weight gain can occur. The cells may be getting more glucose than they need, and the excess glucose is accumulating as fat.

Also, a person who takes insulin for diabetes may be gaining weight if they eat more due to concerns about developing hypoglycemia, or low blood sugar.

It is important to keep having insulin doses on schedule, as skipping any can cause long-term complications.

Effective ways to avoid insulin-related weight gain include:

Tracking calories

People with diabetes often focus on managing their carbohydrate intake. But it is just as important to track overall calorie consumption.

Eating too many calories can lead to excess blood glucose levels and increased fat storage. This may be especially true when a person takes insulin.

Measuring out portion sizes and keeping a food record can help prevent a person from eating more calories than their body needs. Over time, people learn which portion sizes work best for them and no longer need to measure and track their food intake.

Exercising regularly

Regular exercise keeps the body healthy and strong. It also helps burn calories, regulate blood glucose levels, and promote fat loss.

The World Health Organization (WHO) recommends that adults aged 18–64 aim for at least 150 minutes of moderate-intensity exercise each week.

Findings from a 2019 review suggest that structured exercise programs could have significant benefits for people with insulin resistance and type 2 diabetes.

Working with a healthcare team

Healthcare professionals can share valuable resources for people aiming to maintain a healthy weight. They can recommend ways to improve health while reducing the risk of diabetes, obesity, and cardiovascular disease.

Medical professionals can, for example, test glucose and insulin levels and assess a person’s lipid profile. People can use this information to track their progress as they work toward health goals.

The American Diabetes Association’s 2019 guidelines state that “There is not a one-size-fits-all eating pattern for individuals with diabetes, and meal planning should be individualized.”

Registered dietitians (RDs) can recommend foods to eat and avoid, based on a person’s health status and goals. RDs can even develop personalized meal plans.

Certain foods may help prevent weight gain. Developing a meal plan with a balance of nutritious foods can help.

High-quality, unprocessed foods contain less added sugar and fat. They increase feelings of fullness, which may help prevent overeating.

When developing a meal plan, a person should focus on:

  • whole grains
  • vegetables
  • fruits
  • yogurt
  • healthy fats, such as avocados, nuts, and plant-based oils

A person should avoid:

  • refined carbohydrates
  • packaged or processed foods
  • added sugars
  • trans fats

Insulin is a hormone that plays several essential roles. It regulates blood sugar levels, promotes fat storage, and helps break down fats and protein.

Having too much insulin in the body, due to insulin resistance or treatment that does not manage diabetes well, can lead to weight gain.

Several self-care strategies can help prevent insulin-related weight gain. Getting regular exercise and having a diet that focuses on unprocessed foods, such as fruits, vegetables, and whole grains, can help.

If these approaches are not effective enough, consider contacting a healthcare professional. They can provide valuable guidance and resources for anyone looking to have and maintain a healthy weight.

Below are answers to common questions about weight gain from insulin therapy.

Can insulin injections cause belly fat?

Insulin can lead to overall weight gain, but it does not lead to isolated weight gain in the belly area.

Which insulin injection does not cause weight gain?

All types of insulin can lead to weight gain. However, studies show that insulin determir (Levemir) may lead to less weight gain than insulin glargine (Lantus) and intermediate-acting insulin.

Does insulin increase hunger?

Research shows that insulin can increase hunger. It can also increase a person’s perception of sweet flavor and lead them to eat more.