Are Your Meds Making You Fat?

One of the frustrations of diabetes is the way everyone tells you to lose weight. Then they give you medicine that makes you gain weight. Some of the worst offenders are insulin[1] and the thiazolidinedione[2] drugs, pioglitazone (brand name Actos) and rosiglitazone (Avandia). Why do these drugs cause weight gain, and what can you do about it?

To recap: As you know, Type 2 diabetes[3] is a disease of insulin resistance[4]. Your muscle and brain cells don’t want the glucose that the insulin is trying to bring, so they resist. The glucose stays in the bloodstream.


At first, the beta cells[5] in the pancreas try to compensate by pumping out extra insulin to overcome the resistance. When the beta cells can’t keep up, or when the resistance gets too severe, you start running high blood sugar and developing symptoms of diabetes.

When Insulin is Low
People with Type 1 diabetes[6] don’t make enough insulin, period, and people with Type 2 develop a low-insulin situation over time. What does that do to you? With insufficient insulin, glucose can’t get into your muscle and brain cells to be burned as fuel. It can’t get into the liver to be stored as starch, and it can’t get converted into fat. Why not? Because insulin does all those things.

So, when you don’t have enough insulin, you won’t gain weight, because your body can’t do anything with the glucose, and you wind up urinating it away. That’s why weight loss is a classic symptom of Type 1.

Then You Inject
Now this is the tricky part—if you have Type 2, and you are given insulin, the fat storage will resume full speed. Insulin resistance doesn’t affect fat storage. But because of insulin resistance, you will get only a partial improvement in glucose uptake by your muscle and brain cells. So the glucose starts to get stored as fat instead of being lost in the urine. The result is weight gain.

There are other reasons for insulin-related weight gain. Christine McKinney, M.S., R.D., C.D.E.[7], of Johns Hopkins University explains that if people experience hypoglycemic[8] episodes on insulin, they will likely eat more to avoid them. Also, when people find out they can eat whatever they want but avoid high blood glucose by taking more insulin, some react by blowing off their diet. Insulin may also increase appetite directly, she says.

Actos and Avandia, the TZD (thiazolidinedione) drugs, can also cause significant weight gain. In studies[9], the more Actos people took, the more weight they tended to gain. Taking Actos with insulin increased the weight gain. The reason is that a TZD helps a person’s insulin work better, so less sugar is lost in the urine.

What Can You Do About It?
The Mayo Clinic[10] says that weight gain is avoidable with insulin. But you have to cut calories significantly. A lot. With insulin, your body uses food more efficiently, so you just don’t need as much of it. Mayo gives the usual advice about fruits, vegetables, whole grains, smaller portions, not skipping meals, and getting much more physical activity.

If you’ve ever had a bout of hypoglycemia, it’s important to figure out what caused it. If you don’t know, you’ll probably eat more to avoid another one, and you’ll gain weight. If you find that insulin is increasing your appetite, you may want to eat more vegetables or drink more water to suppress hunger. But some drugs can also help.

In the Actos studies, people who took metformin[11] (Glucophage and other brand names) along with Actos gained less weight. In fact, metformin is used as a weight loss drug[12] in psychiatric patients, because some of the psych meds cause a lot of weight gain.

Another diabetes drug that causes weight loss is exenatide[13] (brand name Byetta). Byetta is a synthetic version of a protein originally found in Gila monster saliva, but don’t let that stop you. This drug stimulates the beta cells to produce insulin, but not all the time. Only when blood glucose is up.

More important for the weight thing, Byetta can reduce appetite and delay food absorption. So if you’re trying to lose weight with diabetes, you might look into this drug. But it is injectable, and it is expensive. (If cost is a problem, I guess you could go out and get your own Gila monster.)

Wish We Had Better
I’m sorry that I don’t have any magic solution for this. I think it’s just such a shock to people who have been wasting glucose for so long, that when they finally get on insulin and start using glucose better, they can’t believe how much less they need to eat and/or how much more exercise they need to get. Going on insulin really is a major life challenge.

Does anyone else have any tricks or strategies? Anyone with Type 2 who has started insulin and not gained weight? Or figured out how to lose it back? Let us know.

  1. insulin:
  2. thiazolidinedione:
  3. Type 2 diabetes:
  4. insulin resistance:
  5. beta cells:
  6. Type 1 diabetes:
  7. Christine McKinney, M.S., R.D., C.D.E.:
  8. hypoglycemic:
  9. studies:
  10. The Mayo Clinic:
  11. metformin:
  12. is used as a weight loss drug:
  13. exenatide:

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David Spero: David Spero has been a nurse for 40 years and has lived with multiple sclerosis for 30 years. He is the author of four books: The Art of Getting Well: Maximizing Health When You Have a Chronic Illness (Hunter House 2002), Diabetes: Sugar-coated Crisis — Who Gets It, Who Profits, and How to Stop It (New Society 2006, Diabetes Heroes (Jim Healthy 2014), and The Inn by the Healing Path: Stories on the road to wellness (Smashwords 2015.) He writes for Diabetes Self-Management and Pain-Free Living (formerly Arthritis Self-Management) magazines. His website is His blog is

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