Why You Should Stop Eating Before You Feel Full

Our brains and our stomachs are intrinsically — and biologically — connected. What that means in practice is that our stomachs attempt to inform our brains that we have eaten enough. Harvard Medical School names two hormones at play: cholecystokinin (CCK), which is released when food reaches the small intestine, and leptin, which amplifies the CCK message and imparts a feeling of pleasure.

But, as Stack explains, it takes time for those messengers to reach the brain and make your fullness known. So, it's perfectly possible to overeat in that period. One reason for this is that people like to eat quickly (per Society19). This can be seen in how fast food is winning out over full-service restaurants. Stack continues by noting that the more you ignore the message that you're full, the more your stomach gets used to delaying the message. So, the cycle of overeating becomes biologically ingrained.

The solution isn't to count your calories, however. Harvard Health Publishing emphasizes that "counting calories doesn't work," and there seems to be some consensus on this point. The reason it doesn't work, as explained by Kelsey Borrensen for HuffPost, is that when she was counting calories, she didn't listen to her body, but fixated on a numbers game that didn't holistically address what she ate. One issue is that if you focus purely on calories, you might pass over healthy food that is nutrient-rich and dense just because it doesn't meet an arbitrary metric.

The reason you should stop eating before you feel full is that your stomach fills before you feel it. According to WebMD, it takes about 20 minutes for your brain to register the sensation of fullness. The trick, then, would be to stop at the point where your stomach would inform you it is full. That "trick," in fact, is behind the Okinawan expression "hara hachi bu" — which roughly translates to "80% full." 

"The beautiful thing about the Okinawa diet is the Confucian practice of hara hachi bu — meaning you eat until you're satisfied, not full," Nora Minno, RD, told Well+Good. Hara hachi bu could be described as intentional eating or eating mindfully. As with the counting calories example, you are not consuming to reach a number but are communicating with your stomach to see if it has gotten what it needs.

HuffPost cautions that it takes about 15 to 20 meals before you reset your body's definition of fullness. Registered dietician Susan Dopart tells HuffPost that people looking to recalibrate their eating habits should see how they feel after eating half of their normal portions. SFGate offers a few more rules of thumb. If you drink water before eating, you will notice how empty you feel. As you eat, that emptiness will diminish. A second trick is to notice when pressure builds in your stomach. A gentle, not uncomfortable feeling of pressure is a good indicator to stop consuming food.