It’s possible to gain weight from treating too many bouts of hypoglycemia. I addressed this topic over a decade ago, but it remains relevant and worth revisiting, along with addressing some new insights on weight gain in general with insulin use.
Weight Gain from Treating Lows
Although you can’t avoid treating a low, everything you use contains calories (at least until mini and nasal doses of glucagon are available) and those extra (albeit medically necessary) calories can still end up as excess body fat. Some heavily training athletes have reported gaining fat rather than getting leaner from all their workouts due to chasing a lot of exercise lows. Avoid gaining extra body fat by treating each low precisely to limit calories. Don’t just grab the nearest candy bar when it may take just one glucose tablet to bring your blood glucose back to normal if you have minimal insulin on board.
The best advice is to start with 4 to 15 grams of a rapid-acting sugar (preferably glucose), and only take in more glucose or follow it with a balanced food or drink if your low doesn’t resolve itself within 10 to 15 minutes or if you anticipate needing protein or fat in your system to prevent later lows, such as after a long workout or if you took too much insulin. Overtreating your lows just leads to rebound hyperglycemia, more insulin to bring it back down, and potentially another low later — followed by more calories and potential weight gain.
Weight Gain from Insulin Use
In addition to lowering blood glucose, the hormone insulin promotes fat storage, and if you often end up taking too much, it can make you gain extra fat weight. You can adopt some strategies to keep weight gain from happening from insulin or other diabetes medications, regardless of what type of diabetes you have.
Why is using insulin often associated with weight gain? When you use it, your blood glucose is (usually) in a tighter range, and you stop losing some calories as glucose in your urine like you do when your blood glucose is running on the high side. Also, as mentioned, you can gain weight from having to eat extra to treat any lows caused by insulin or other medications. (Remember, even if you have no other choice than to treat hypoglycemia, calories are still calories.) You may find that cutting back on refined carbohydrates that require more insulin to cover them, exercising regularly, and checking your blood glucose to avoid taking too much of any weight-inducing medications will help you avoid gaining fat weight.
Most people diagnosed with type 1 diabetes gain some weight as soon as they start using insulin. Many of them lost weight before diagnosis — some of it muscle — so not all the weight regain is necessarily bad (some is from muscle mass). However, you can gain excess weight from taking too much daily insulin and treating lows or even from taking the right amount of insulin but eating too many calories.
It’s advisable to not give up exercise, but you should still avoid gaining extra fat if you can because it is often associated with being more insulin resistant and may require you to take even larger doses of insulin. You can lower your insulin needs by staying regularly active. Readjusting your ratio of basal to bolus insulin — specifically, lowering your basal doses and raising your pre-meal insulin — without increasing your total daily insulin dose may also prevent weight gain with type 1 diabetes.
Also, try to keep your insulin needs as low as possible because the more you take, the greater your potential for causing lows that lead to weight gain is. During any physical activity, your muscles can take up blood glucose and use it as a fuel without insulin. Following exercise, your insulin action is heightened for a few hours up to 72 hours. During that time, you need smaller doses of insulin to have the same effect. With that in mind, adjust your insulin doses downward to prevent lows after exercise that cause you to take in extra calories to treat them.
Finally, you may be able to avoid weight gain by looking at the type of insulins you’re using. For example, once-daily Levemir used by people with type 2 diabetes causes less weight gain and less frequent hypoglycemia than NPH insulin, even combined with use of rapid-acting injections of meal insulin. The same is likely true when using Lantus, Basaglar, Toujeo, and Tresiba. In type 1 diabetes, individuals end up eating less when using Levemir compared to Lantus, leading them to gain less weight. It also helps to dose with fast-acting insulins for the amount of food you actually eat rather than eating to match your pre-meal insulin doses.