For those who need science as soon as possible, science delivery team AsapSCIENCE is usually on the ball. This week, they teach us exactly how appetite works, and why we overeat even though we know that, logically, we shouldn’t be hungry. It’s a little more complicated than you might think. Watch the video and read on to figure out why you finished that entire party-sized bag of chips the other day.
The reason why we overeat, and why we generally overeat with junk food is one part bodily chemistry, one part evolutionary instinct, and one part because junk food tastes so darn good. When a stomach is empty, it releases the hormone Ghrelin, which tells that brain that it needs to hurry up and dump some food into the stomach. After we eat, Ghrelin subsides and the stomach releases the hormone Leptin, which tells us to put down the fork. However, scientists believe evolutionary instinct is the reason why you might have found yourself saying, “Well, I always have room for dessert,” after eating a 16-ounce steak and about a pound of mashed potatoes. Fat and sugar make food taste great, but they’re also a high source of energy, and scientists believe that once upon a time in humanity’s early days, that kind of food was scarce, so we developed a strong desire to get our hands on it. The great taste and high energy payoff seems like a winning combination.
On top of the theorized evolutionary aspect, it turns out that a steady and high intake of fat and sugar overrides the regulated management of Ghrelin and Leptin production, so coupled with our evolutionary instincts, we pretty much can’t help ourselves. As AsapSCIENCE puts it here and Terry Pratchett put it in Good Omens, the more unhealthy food you eat, the more you want it.
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