Apples and Oranges, Diabetes and Obesity

Headlines this week have been suggesting that a little extra weight might be good for people with type 2 diabetes. Unfortunately, they’re comparing apples and oranges and confusing the relationship between diabetes and obesity.

The confusion comes from a study published in the Annals of Internal Medicine that compares the outcomes of people who have type 2 diabetes despite not having any excess weight with people who have type 2 diabetes along with excess weight or obesity.

What they found is that people who have type 2 diabetes without any excess weight don’t live as long as people who have type 2 diabetes along with excess weight. And people with obesity do just as badly as the first group.

What it really means is that having type 2 diabetes at a low BMI is worse than having diabetes that results from carrying excess weight. There’s no evidence and no reason to believe that a little extra weight would help the people who have type 2 diabetes despite a normal weight.

The title of the study itself is misleading because it conjures up an “obesity paradox in type 2 diabetes.” The study found no paradox in people with obesity and type 2 diabetes. They do just as poorly as any group in the study. And did we mention that they had more heart attacks and strokes?

Let’s go back to what we know about excess weight and diabetes. We know that excess weight frequently causes type 2 diabetes. We know that losing excess weight can prevent or reverse diabetes. Apart from causing confusion, the only thing this new study adds is a hint that people who have type 2 diabetes even without excess weight may well have a worse form of the disease.

There’s no evidence of weight having a protective effect. There’s just an association with lots of possible confounding factors at work.

Click here to read the study and here to read more from Reuters.

Laurel and Hardy, photograph © twm1340 / flickr

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