Hearing you need to go on insulin to manage your diabetes can spark a flurry of Google searches about what, exactly, this means for your health and life going forward. And, while insulin can play a crucial role in helping you live a happier, healthier life, you might have heard at some point that taking insulin can make you gain weight.
Obviously, getting your diabetes under control is priority No.1 but…is there any truth to this? Does insulin make you gain weight? Turns out, the answer is a little nuanced. Here’s what you need to know.
What is insulin, exactly?
Insulin is a vital hormone that you can’t survive without. It helps regulate blood sugar (a.k.a glucose) in your body and ensure that it can enter your body’s cells, where it can be used for energy.
When you have type 1 diabetes, your body doesn’t make enough insulin or any at all. With type 2 diabetes, your pancreas (an organ that helps with digestion and secretes certain hormones to regulate sugar in your body) doesn’t make enough insulin and your cells respond poorly to the hormone. As a result, they take in less sugar.
Blood sugar can then build up in your body, causing a range of symptoms like increased thirst, extreme hunger, fatigue, and unintended weight loss.
Why do some people with diabetes need to take insulin?
If you have type 1 diabetes, you need to take insulin because your body is no longer making it. That usually translates to taking insulin several times a day, including with meals. Some people will use an insulin pump, which delivers small, steady doses throughout the day, while others prefer to give themselves injections.
Some people with type 2 diabetes can manage their disease through lifestyle changes (like diet and exercise). But others may need to add certain medications and even insulin to help keep their blood sugar under control.
Not all insulin is created equal, though. Here’s a little breakdown of the types and how they work:
- Rapid-acting. This form of insulin starts working about 15 minutes after you inject it, peaks an hour later, and lasts anywhere from two to four hours.
- Short-acting. This insulin goes to work within 30 minutes, peaks two to three hours later, and lasts between three and six hours.
- Intermediate-acting. This type of insulin starts working two to four hours after you inject it, peaks after four to 12 hours and lasts for 12 to 18 hours.
- Long-acting. Long-acting insulin goes to work several hours after you inject it, does not peak, and lasts 24 hours or more.
So, does insulin make you gain weight?
It depends on what your health was like before you went on insulin, says endocrinologist Dr Rachael Oxman. “When diabetes is severely uncontrolled, people frequently have had unintentional weight loss despite eating normally,” she explains. “This is really unhealthy for their bodies. When they start insulin, they are finally able to make proper use of the kilojoules and carbohydrates in their food and with this comes weight regain.”
Diabetes expert Dr Mark Schutta, agrees. When your blood sugar is chronically high “you are in a relative starvation state,” he says. Because of this, Dr Schutta says, “you’re consuming food and your body isn’t properly absorbing the nutrients.” Hence, weight loss.
People who experience high blood sugars for a (very) prolonged period of time may have lost 9kgs in a few months, Dr Schutta explains. “When you give them insulin, you’re getting their blood sugars under reasonable control and [they're] generally going to regain the weight, often within a matter of weeks.” While that can feel like taking insulin made someone gain weight, it actually is just restoring them to their normal weight, he points out.
It can also take a little trial and error to figure out the right balance of the food you’re eating with the amount of insulin you need, says endocrinologist Dr Ronald Tamler. “Insulin is a necessary key to use—or store—the energy from carbs,” he says. “If one matches the amount of carbs one is eating to one’s daily needs, weight should stay the same.”
The amount of insulin you need can be a factor, too, Tamler says. “Some patients on insulin treatment may still experience weight gain, especially if they have to take larger amounts of insulin to keep up with their body’s needs,” he says. So at the end of the day, weight gain can really depends on a slew of factors, beyond just the amount of insulin you need.
How can you manage your weight when you take insulin?
Doctors stress that taking less insulin than what your doctor recommends or stopping it altogether is not the way to go. “Stopping insulin use in order to lose weight is a dangerous strategy that may lead to an emergency called diabetic ketoacidosis or hyperosmolar hyperglycemic syndrome,” says endocrinologist Dr Disha Narang. Diabetic ketoacidosis is a serious condition that can lead to a diabetic coma or even kill you. Hyperosmolar hyperglycemic syndrome can also cause a coma.
Instead, they suggest keeping tabs on what you’re eating. “If you are aiming to lose weight, you can try decreasing the number of carbohydrates in your meals and increasing vegetables and lean proteins,” Dr Oxman says. That should naturally lower your insulin doses (because you're eating fewer carbohydrates) and help with weight loss over time.
If you notice you’re gaining weight and it bothers you, Dr Schutta suggests checking in with your doctor about the type of insulin you’re using and the timing of it. “You can try to anticipate how much short-acting insulin you’ll need before your meal and take it 15 minutes before you eat,” he says. “If you’re able to time it right, you have a better chance of making it peak at the time your blood sugar is peaking—that’s what you want it to do. If you time it that way, you’re ultimately going to need less insulin.”
It’s also a good idea to talk to a dietitian who specialises in diabetes management to learn how to optimise your insulin demand, Dr Tamler says. That, he says, can help you “identify high-carb foods” and learn how to adjust your lifestyle to lower your insulin needs.
Dr Narang agrees. “A lower amount of insulin is needed for a lower carbohydrate, higher-fibre, or higher-protein meal. A moderate dietary pattern with mindfulness over quality of carbohydrates can help in mitigating weight gain.”
The bottom line
At the end of the day, what's most important is that your body is getting what it needs to thrive. And for diabetics that are recommended insulin therapy, that means taking insulin as prescribed. So insulin should not be the enemy, but rather another tool in your wellness toolbox. “It is important to work with your doctor and medical team to make sure insulin dose adjustments are made so that one does not have such extremes in blood sugars,” Dr Narang says.