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Stop Overeating: Try This 300-Year-Old Japanese Eating Habit

June 30, 2025

Most of us don’t just overeat on holidays. It happens on ordinary Tuesdays too—at restaurants, in front of the TV, or just because something tastes really good. 

In fact, when researchers asked a group of men to eat Domino’s pizza until they were “comfortably full,” they still consumed, on average, 1,600 calories. When they ate until they “couldn’t eat another bite”? Over 3,100 calories.¹

It’s a centuries-old practice still common in Japan today, especially in Okinawa, where people have some of the lowest rates of chronic disease and some of the longest lifespans in the world.

But this isn’t just cultural tradition—it’s a practical, doable way to reset your relationship with food. It helps you eat what your body actually needs, not just what your taste buds want in the moment. 

And when practiced consistently, it can improve digestion, reduce mindless overeating, and increase satisfaction from every meal. I’ll show you how.

Why Eating to 80% Full Works

Most of us try to eat until we’re full—but not stuffed. The problem is, that full feeling doesn’t kick in right away. 

It takes a few minutes for your brain to register what your stomach already knows. So you keep eating… and suddenly you’ve gone past the point of satisfied.

Today’s food environment only makes that easier to do. 

Ultra-processed foods—packed with excess sugar, fat, and salt—are engineered to keep you eating. They drown out your body’s natural satiety signals and make it harder to tell when you’ve had enough.

That’s where hara hachi bu comes in. By stopping at around 80% full, you give your body time to catch up. A few minutes later, satiety sets in—and you realize you did indeed get plenty.

Case in point: Researchers at Ochanomizu University found that men who always practiced hara hachi bu ate 500 fewer calories per day than those who rarely or never used this approach.² (The regular practitioners  of “eat to 80% full” also consumd two more servings of vegetables per day.) 

What’s more, women who followed hara hachi bu had significantly lower BMIs than those who only sometimes ate this way.

While this practice might be especially helpful if you eat out often or rely on packaged foods, hara hachi bu benefits anyone who wants to feel better after eating. 

Even with whole foods, stopping at 80% can help you avoid that too-full feeling, stay energized, and walk away from meals feeling light, clear-headed, and more in tune with your body.

How to Master Eating Until 80% Full

There’s no app or number that will tell you when you’re 80% full. But with a little practice, you can feel it. 

Think of it as a skill you build over time, not something you have to get perfect on day one. 

Here’s how to start:

• Eliminate distractions. Turn off the TV, put away your phone, and eat without multitasking. It’s hard to notice fullness cues when your attention is somewhere else.
  
  
• Eat slowly. This gives your body more time to register what you’re eating—and makes it easier to stop when you’ve had enough. Put your fork down between bites. Take a breath. Notice the flavors. (Read More: The Science of Slow Eating.)
  
  
• Use the movement test. As you near the end of your meal, ask yourself: “Would I feel good doing yoga or going dancing right now?” If the answer is yes, you’re probably in that sweet spot—satisfied but not weighed down.
  
  
• Notice how you feel afterward. When you stop at 80%, check in 10, 20, and 60 minutes later. Are you still satisfied? How’s your energy? Do you feel light and comfortable? Compare that to how you feel when you eat past fullness. You don’t need to track this forever—but keeping a quick journal for a week or two can help you connect the dots. The more you notice how good it feels to stop at 80%, the easier it becomes to do it next time.

Noticing how your body responds after meals—how full you feel, how your energy shifts, how your mood changes—is a form of body awareness called interoception.

It’s your ability to sense internal signals like hunger, thirst, and satisfaction. The more you tune in, the more natural it becomes to eat just enough—without counting, restricting, or relying on willpower.

Over time, that builds a stronger connection between how much you eat and how much your body actually needs—turning every meal into a chance to feel good, not just full.

References

1. Hengist A, Edinburgh RM, Davies RG, Walhin J-P, Buniam J, James LJ, et al. Physiological responses to maximal eating in men. Br J Nutr. 2020 Aug 28;124(4):407–17. 

2. Fukkoshi Y, Akamatsu R, Shimpo M. The relationship of eating until 80% full with types and energy values of food consumed. Eat Behav. 2015 Apr;17:153–6. 

3. Willcox DC, Willcox BJ, Todoriki H, Curb JD, Suzuki M. Caloric restriction and human longevity: what can we learn from the Okinawans? Biogerontology. 2006 Jun;7(3):173–7.