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You've no doubt heard of "free radicals", those nasty chemicals that seem to contribute to heart disease, cancer and all sorts of human ailments. Maybe you even take antioxidant vitamins to help get rid of these unwanted toxins. Well, maybe you shouldn't. Because a new study in the journal Cell Metabolism suggests that, when it comes to diabetes, free radicals can be good for you-and and antioxidants might make things worse.

Free radicals can damage vital cell components, and our bodies produce them naturally as we metabolize food. So, it stands to reason if we eat lots and lots of food, we'll make tons of radicals. And put ourselves at risk of becoming seriously obese, and developing diabetes. All of which is bad.

But it's actually not that simple. You see, in addition to being potentially harmful, free radicals are also necessary for cells to communicate. In particular, they help muscle cells respond to insulin. So, mice that can't get rid of their free radicals actually do well on a high-fat diet, and it's only when they're given antioxidants that they get diabetes. If all that makes your head hurt, go for a nice walk. Because exercise is still good for you.