You may have heard that insulin causes weight gain. Let’s take a look.
It is well-established that one of the primary functions of insulin is to facilitate fat storage. In theory, fat storage should only happen when there is enough energy to store, that is, when you’ve eaten more calories than your body needs.
Every human and animal on earth needs insulin to survive and thrive. For those without diabetes, the pancreas efficiently pumps out the amount of insulin required to keep blood glucose levels normal around the clock, constantly adjusting in response to numerous variables, like meals or stress.
Is there something different about using exogenous insulin injections, as opposed to the insulin produced by the healthy human body, that will cause people to gain undesirable weight?
Type 1 Diabetes and Insulin
In type 1 diabetes, an autoimmune attack destroys the cells that produce insulin. With little or no insulin, the body cannot turn food into energy or fat, which is why undiagnosed patients often lose weight. Such patients will typically regain weight rapidly once they begin to administer insulin. This is a good and very healthy effect of proper treatment, restoring patients to their proper weight levels.
Historically, the stereotypical patient with type 1 diabetes has been thought to be lean. For the most part, this was a sad consequence of the effect of chronic hyperglycemia.
Today, patients with type 1 diabetes are better able to achieve good glucose control, thanks to improvements in insulin formulations and diabetes technology, and a better understanding of the condition. As a result, patients have caught up to the general population and are now no more or less likely to be overweight. While it’s a very good thing that fewer patients suffer from unintended weight loss due to high blood sugars, it’s also true that an increasing number of people with type 1 diabetes are now overweight or obese. Patients with obesity are more likely to develop extreme insulin resistance and “double diabetes,” an especially challenging condition.
In theory, as we said above, exogenous insulin injections shouldn’t cause excess weight gain unless you are also eating too much food. The reality may be more complicated.
Both clinical trials and the diabetes community’s anecdotal reports suggest that insulin treatment does cause weight gain. The DCCT, the most rigorous major trial in the history of type 1 diabetes, found that patients using intensive insulin treatment gained 10 pounds more than patients using less insulin. (They also enjoyed massive health improvements due to their improved blood sugar levels.)
It’s not entirely clear why this happens. Part of it may be that insulin that is injected under the skin is not precisely the same as insulin secreted by the pancreas. Experts have theorized that, for example, subcutaneous insulin injections (or infusions) have “‘unphysiological’ pharmacokinetic and metabolic profiles” that introduce some metabolic dysfunction that could cause extra weight gain.
Another potential explanation for weight gain is the frequency of hypoglycemia, which often compels those of us with type 1 diabetes to overeat in order to get our blood sugar levels back up. Just the fear of low blood glucose events may cause some patients to consciously overeat.
But there is no reason to assume that insulin-associated weight gain is inevitable. As we discuss below, there are several modifiable factors that can help you increase your insulin sensitivity, which may help you keep your weight in check.
Type 2 Diabetes and Insulin
Many people with type 2 diabetes are worried about insulin making them heavier. It is one of several diabetes other medications that have been linked to weight gain.
Most experts seem to believe that initiating insulin treatment does provoke weight gain. And because excess weight is highly associated with diabetes progression and complications, it is especially important for people with type 2 diabetes to favor treatments that are less likely to create weight gain.
The research, however, isn’t completely unanimous. One 2014 study on the topic determined that while higher doses of insulin did cause additional weight gain, other factors, such as baseline BMI and A1C, were also important, suggesting that insulin-associated weight gain is complex and inconsistent. Another research study found that “insulin-associated weight gain in type 2 diabetes is associated with increases in sedentary behavior” as opposed to the chemistry of insulin itself.
As with type 1 diabetes, “defensive snacking” to prevent or correct hypoglycemia can also contribute to overeating and therefore caloric excess and weight gain, particularly for patients using bolus insulin therapy.
Tips for Preventing Excess Weight Gain on Insulin Therapy
- Eat healthier: Whether you are using insulin therapy or not, some diets are better for weight maintenance than others. Hyperpalatable junk foods, and other foods that combine sweet, starchy, salty and fatty flavors, are basically engineered to compel you to overeat. Minimally-processed foods, especially those with plenty of fiber and protein, can help you feel fuller faster and reduce the drive to overeat.
- Make sure your insulin doses are set correctly: Using too much insulin for your needs will cause hypoglycemia and lead to overeating, which may lead to unwanted weight gain.
- Treat low blood glucose with precision: Using specific amounts of glucose and not over-treating low blood glucose can go a long way toward helping you not consume too many calories (and have to take additional insulin from overcorrecting).
- Exercise regularly: Exercise may be the best way to improve insulin sensitivity, allowing you to use smaller doses of insulin without risking blood sugar rises. Exercise also plays a big role in maintaining your weight.
- Choose water: Sometimes, when we feel hungry, we may just be thirsty, and choosing water is an essential step to being hydrated, and feeling fuller. It’s a healthy beverage that will not spike your blood glucose levels. For those looking to avoid weight gain, saving your calories (and insulin) for your meals is a great idea.
Insulin causes the body to store fat and gain weight, and many people with diabetes gain weight upon beginning insulin therapy.
Weight gain is not inevitable, and there are several things you can do to try and maintain your weight: speak to your doctor about adjusting your insulin dosing strategy; choose foods high in protein and fiber that require less insulin and are less likely to provoke overeating; exercise regularly to enhance your insulin sensitivity.
It is a good idea to talk to your healthcare provider for help with insulin dosing or related questions about diet, exercise, weight, and appropriate medication adjustments.
Read more about A1c, diabetes weight gain, exercise, insulin, Intensive management, low blood sugar (hypoglycemia), weight gain.