Does Insulin Cause Weight Gain?

Insulin therapy to manage blood sugar levels can contribute to weight gain. This can be concerning for many people who have diabetes because increased weight can make diabetes more difficult to manage.

Research shows that even just a 10% weight loss can increase insulin sensitivity in people who are overweight, so weight gain could make you more resistant to insulin.

There are ways that you can prevent weight gain while on insulin, and it's even possible to lose weight while taking insulin.

Diabetic woman injecting herself with insulin

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Why Insulin Causes Weight Gain

Insulin is a hormone that is produced by the body that helps control the amount of sugar that is in the blood. Insulin acts as a gatekeeper between the blood and cells for blood sugar because it is responsible for bringing sugar into cells from the blood to be used as energy or stored for later use.

When you're not producing enough insulin or when you become less sensitive to insulin, there ends up being elevated levels of sugar in the blood, leading to diabetes. Depending on the cause of your diabetes, your healthcare providers will recommend different types of medications to help with managing your diabetes, and one of these is insulin therapy.

The reason that insulin could cause weight gain is that when you start insulin therapy, all of the extra glucose in your blood is brought into the body to be used as energy or stored. As you become more efficient in using the carbohydrates you eat, your body stores more of that energy as fat if it is more than you use that day.

Never Stop Taking Insulin Because of Weight Gain

It's important to remember that if you were prescribed a medication like insulin, it was for a good reason. Take all of your medications as prescribed and never stop taking your insulin as a way to lose weight.

Multiple complications can develop from uncontrolled diabetes, such as:

It is important to take your medications as prescribed to keep your blood glucose levels in a normal range.

Tips to Avoid Weight Gain

Focusing on both your diet and how much you're moving throughout the day are two of the most important things that you can do to help with controlling your weight.

You don't need to go through these changes alone. Build a support system of friends, attend group diabetes management classes, or work with a dietitian one-on-one so they can answer your questions and support you while you are making lifestyle changes.


Insulin is only able to cause weight gain when there is extra glucose from the blood that you don’t need for energy. That means an important part of avoiding weight gain is monitoring your total calorie intake.

Your weight is the balance between the number of calories you eat versus the number of calories you burn. Watching your portion sizes and the type of food that you eat helps to prevent weight gain.

Aim to have mostly nutrient-dense foods in your diet, meaning foods that have large quantities of vitamins, minerals, and fiber in comparison to the number of calories it has.

Balance Your Plate

Try to eat a balance of different types of foods to get a variety of nutrients in your diet. Aim for the bulk of your food to come from:

  • Vegetables
  • Fruits
  • Whole grains
  • Healthy fats
  • Lean proteins

Tips for making sustainable diet changes to maintain a healthy weight include:

  • Eating for your physical hunger. Often our food choices can be guided by other reasons like emotions, boredom, and habits that can lead to eating when you aren't physically hungry. They can also cause over-eating at mealtimes. Paying attention to your physical hunger can help you to eat enough without overeating by focusing on what your body actually needs.
  • Choosing foods that keep you satisfied. Fiber and healthy fats help to keep you feeling fuller longer, making it easier to not overeat. If you're going to indulge in a treat, choose a smaller portion of the food that will satisfy your craving and allow yourself to truly enjoy that.
  • Not skipping meals. It's important that you aren't skipping meals when you are taking insulin to help manage your diabetes because you could experience low blood sugar if you do. Skipping meals, even when you feel hungry, may seem like a good idea when you are trying to lose weight, but it actually makes it more difficult to lose weight. When you skip meals, it makes you more likely to overeat at your next meal because of how intense your hunger will become.
  • Eating mostly nutrient-dense foods. Aim for most of your foods to come from fruits, vegetables, whole grains, healthy fats, and lean proteins. Watch the portion size of your food to monitor your total calorie intake and total carbohydrate intake.


Being physically active throughout the day is important to increase the number of calories you burn.

How Much Exercise Should I Get Per Week?

It's recommended to do at least 150 minutes of moderately intense activity per week. Exercise can include:

  • Walking
  • Biking
  • Running
  • Dancing
  • Doing work around the house like gardening or vacuuming

It's also recommended to do strength training exercises a couple of times a week.

Research shows that exercise, even without weight loss, improves blood sugar levels and helps with insulin resistance.

When increasing your exercise time or starting a new exercise program, first discuss how this will affect your medications and blood sugar levels with your healthcare provider before starting. Since exercise can affect these, you may need to make adjustments to your medications or have some snacks with you to prevent low blood sugar levels.

Know Your Treatment Options

Stay in contact with your healthcare provider to discuss your treatment options if you are noticing weight gain. There are many different medications that can help with managing diabetes, so discuss any concerns you have with your practitioner to make sure you are on the best medications for your needs.

When making changes to your diet and activity level, it's important to continue to measure your blood sugar levels to stay within your goal range and to see how these are affecting your blood sugar.

Other Medications and Weight Gain

Discuss all the medications that you're taking with your healthcare provider and ask if any other side effects are weight gain. See if changing your medication could help with maintaining a healthy weight.

A Word From Verywell

Weight gain while taking insulin is normal and it doesn't mean that anything has gone wrong. Managing a chronic illness like diabetes is a lifelong process that takes time to learn how to best manage it for you.

When you start to learn how your body responds to insulin, you can use that information to make adjustments to your treatment plan. Discuss any questions you have with your healthcare provider to create a treatment plan that is most effective for you. 

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Brown A, Guess N, Dornhorst A, Taheri S, Frost G. Insulin-associated weight gain in obese type 2 diabetes mellitus patients: What can be done? Diabetes Obes Metab. 2017;19(12):1655-1668. doi:10.1111/dom.13009

  2. Clamp LD, Hume DJ, Lambert EV, Kroff J. Enhanced insulin sensitivity in successful, long-term weight loss maintainers compared with matched controls with no weight loss history. Nutr Diabetes. 2017;7(6):e282. doi:10.1038/nutd.2017.31

  3. Centers for Disease Control and Prevention. How much physical activity do adults need?

  4. Duncan GE, Perri MG, Theriaque DW, Hutson AD, Eckel RH, Stacpoole PW. Exercise training, without weight loss, increases insulin sensitivity and postheparin plasma lipase activity in previously sedentary adults. Dia Care. 2003;26(3):557-562. doi:10.2337/diacare.26.3.557

By Ashley Braun, MPH, RD
Ashley Braun, MPH, RD, is a registered dietitian and public health professional with over 5 years of experience educating people on health-related topics using evidence-based information. Her experience includes educating on a wide range of conditions, including diabetes, heart disease, HIV, neurological conditions, and more.