The Checkup: Why You Keep Eating Even When You’re Full

A new study looked at our tendency to stuff ourselves silly.

• We’ve all done it: You just finished a delicious meal—say, Thanksgiving dinner—and the platters and dishes of leftovers are still in front of you. So you start picking: another scoop of potatoes, a half-piece of turkey, a tablespoon of cranberry sauce. Even though you’re full, you just keep eating. And eating. And eating. Until at some point, you realize, well, you sorta feel sick. Turns out, there’s a name for this: hedonic hunger. Researchers in Italy recently studied the phenomenon and found that humans seem to be hard-wired to stuff themselves silly. It all goes back to our ancestors, who often faced food shortages so, when presented with more food than they calorically needed, they ate and ate and ate anyway, past the point of being full. It was a survival instinct, because who knew when the next meal was coming? Problem is, we still have those instincts, even though most of us don’t face food shortages. So this study looked at the physiological underpinnings of this instinct, and found that two chemicals, which regulate appetite and reward, soar when we’re presented with our favorite foods even after we’re already full—which seems to make us continue to eat. Admittedly, the study was small—it involved just eight participants—so researchers say their findings are preliminary at best. But it sure seems like they’re on to something, don’t you think?

• Presenting: the biology of a sneeze, compliments of Penn Medicine.

• Repulsed by meat? It might be in your genes.