This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
It’s well established that stress can lead to obesity and diabetes. How can that be? Well, you have to consider what stress is, exactly. Biologically speaking, stress is when you prepare yourself to deal with a perceived threat. So your brain activates your adrenal glands—via the release of various hormones—and your blood steam fills with adrenaline. In response, you go into hyperdrive.
But irrespective of your mode of stress, be it fight or flight, your body assumes you’re going to need energy to handle it. So the same hormones also release energy stores. Makes sense, and you of course must also block the body’s ability to store energy. I mean, what’s the point of releasing energy into your blood stream, if you then go and immediately re-store it?
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And there it is: the key to understanding obesity and diabetes with stress. Well, one possible key, in any case. Blocking energy storage, you see, entails making insulin receptors insensitive. Because these in turn control the transport of sugar-based energy into your cells through glucose transporters, insulin insensitivity blocks storage, and it is also one of the key problems in Type II diabetes.
Stress, it follows, is transient Type II diabetes, even when you’re otherwise healthy.
So now that we know what stress is, it’s not much of a leap to imagine that chronic pathological stress can lead to chronic insulin insensitivity: permanent Type II diabetes.
One way insulin insensitivity then leads to obesity is that you need LOTS of insulin before glucose transporters are activated. To get that much insulin pumping, you need to get your blood sugar levels very high. Then, all at once, your glucose transporters finally open, and huge amounts of sugar flood into your cells. More than they need, in fact. So the surplus is stored as fat. And you get obese.