Experts say this Japanese eating tradition may reduce your risk of chronic disease
In the Okinawa diet, a traditional Japanese way of eating emphasising plant-based, whole foods, many people embrace the philosophy of 'hara hachi bu,' the concept of eating until you’re 80 percent full.
Growing up, your parents may have taught you that not finishing your food was against the rules—however, it may actually benefit your health to leave a portion, experts say.
Although hara hachi bu has been practiced for hundreds of years within Japanese culture, it gained popularity in August 2023 when the docu-series Live to 100: Secrets of the Blue Zones debuted on Netflix. The show follows author and explorer Dan Buettner on a trip to the world’s 'Blue Zones' where people live longer than average—including Japan, which has the highest number of centenarians (people who live to be 100 or older) in the world.
There, he witnessed locals practicing 'hara hachi bu' at mealtime. 'This idea teaches each Japanese generation that our portion size is small,' says Asako Miyashita, RDN, a New York-based dietitian who grew up in Japan. In Live to 100, it is believed that this cultural practice may be part of the reason that Okinawa has such a high percentage of centenarians.
If you’re curious about 'hara hachi bu,' its connection to the Okinawa diet and longevity, and how to practice it on your own, here’s what experts want you to know.
Meet the experts: Asako Miyashita, RDN, is a dietitian nutritionist based in New York. Kouka Webb, RD, is a Japanese-British dietitian based in New York City.
What does 'hara hachi bu' mean?
To break it down, 'hara hachi bu' directly translates in Japanese to 'belly 80 percent full,' or eating until you’re 80 percent full, says Kouka Webb, RN, a New York-based dietitian born and raised on 'hara hachi bu' in Japan. Although the idea was born over 300 years ago, it is still a common saying in Japan today, Webb says.
'This phrase dates back to the Edo Period in 1713 when Japanese philosopher and botanist Ekiken Kaibara published his book, Yojokun: Life Lessons From A Samurai,' Miyashita says. The prefix 'yojo' in 'yojokun' stands for 'self-healing ability,' which aligns with the book’s focus on listening to what your body tells you, according to Miyashita. The book introduces the idea of 'hara hachi bun me,' which means to stop eating at 80 percent full.
The philosophy can help with gastrointestinal issues and encourage a healthier mindset, Miyashita says. And 'hara hachi bu' clearly worked for Kaibara, because he lived to be 83, which was rare in the Edo Period—the life expectancy was less than 50 years old, Miyashita says.
As Buettner learned from traveling to Okinawa, many older residents say the phrase 'hara hachi bu' out loud before they eat a meal—a ritual Miyashita says her family did during her childhood. The phrase serves as both a pre-meal blessing and a reminder to stop eating before you are too full.
Benefits of the 'Hara Hachi Bu' approach
You might enjoy meals more.
'Hara hachi bu' encourages people to pay attention to their food, which can enhance enjoyment at meal times, Webb says. 'By focusing on the flavors, textures, and aromas of the food, people may get more satisfaction from their meals,' she adds. 'I also find that for me, hara hachi bu makes me more aware of what and how often I’m eating, which in turn makes the whole dining experience more enjoyable,' she says.
Rather than following a strict diet plan that makes you cut out foods you love, you can continue to enjoy your favorite treats, just at a healthier pace (and without feeling overstuffed).
It can work as a long-term weight loss strategy, however, that’s not its intended purpose.
'Hara hachi bu' is not a diet, but a lifestyle that can help promote a sustainable approach to eating, says Webb. 'It encourages mindful eating and portion control without the need for strict calorie counting or eliminating certain food groups,' she adds. A mindful eating approach can be an important component of weight management and treating obesity, per a 2018 review in the journal Current Obesity Reports. It’s also more sustainable than, say, a highly restrictive diet, she says. If you’re planning on using 'hara hachi bu' as a way to lose weight, you may want to consult with a doctor or dietitian first or enroll in a nutrition course beforehand, Miyashita says.
It may help your body digest food better.
Overeating can cause indigestion and stomach pain, per Cleveland Clinic. When you eat until you’re 100 percent full (and beyond that), you slow down digestion, absorption, and metabolism, Miyashita says. 'This puts strain on organs such as the stomach, intestines, pancreas, kidneys, and liver,' she says.
'By eating until 80 percent full, people may experience less discomfort and reduce strain on the digestive system,' Webb says. 'Eating until you’re 80 percent full is associated with a lower risk of acid reflux, bloating, and gastrointestinal issues.' Hara hachi bu can also help to regulate blood sugar levels, Webb adds. Why? Eating excess calories can lead to weight gain and obesity, both of which are risk factors for insulin resistance and type 2 diabetes, she says. Because hara hachi bu encourages smaller portion sizes (and, in turn, fewer calories), it may help prevent those rapid blood glucose spikes that occur when consuming large meals, she says.
It can help you eat more mindfully.
Women are two to three times more likely to experience anxiety and mood-related disorders and may be more likely to eat in response to stress, a 2021 study in Frontiers in Neuroendocrinology found.
If you catch yourself reaching for more snacks on stressful days, 'hara hachi bu' may support you in developing a healthier relationship with eating.
'‘Hara hachi bu’ can help distinguish between physical hunger and emotional eating,' Webb says. 'Mindful eating can reduce stress and improve an overall sense of well-being.' Feeling satisfied rather than overly full can reduce negative feelings and promote a more positive relationship with food, Webb adds.
It may lower your risk of chronic diseases.
'Eating until 80 percent full is associated with a lower risk of chronic diseases such as cancer, stroke, and heart disease,' Webb says.
Okinawans have far fewer age-related illnesses like diabetes, heart disease, and cancer, according to a 2024 study on longevity in Okinawa. More research is needed to determine whether hara hachi bu is the sole cause of these health outcomes, however, it’s notable that those who practice it—while adhering to a traditional Japanese diet—tend to have lower rates of disease.
Among Okinawans who follow a traditional Japanese diet (including hara hachi bu), the incidence of prostate, colon, and breast cancers is about 50% lower than the rest of Japan, per a 2009 study in the Journal of the American College of Nutrition. In fact, obesity prevalence is only 3 to 4 percent in all of Japan—far less than the UK, where the 25.9 percent obesity rate contributes to chronic disease risk every year.
Potential risks of the 'Hara Hachi Bu' approach
Both Miyashita and Webb have seen benefits from their childhood journey with 'hara hachi bu,' however, they acknowledge that everyone’s eating habits are different, so this concept will impact others in a variety of ways. 'It can be difficult to gauge fullness levels, particularly for people who are not accustomed to mindful eating. This can lead to over or under-eating,' Webb says. 'Individuals may misjudge their fullness and consistently eat too little, which can lead to nutritional deficiencies over time.'
Beginners who have a history of eating disorders, especially anorexia nervosa, may want to be mindful when trying out a method like 'hara hachi bu,' Miyashita says. 'People with eating disorders have lower energy intake than that of people without, therefore, ‘hara hachi bu’ could be dangerous because their daily intake exponentially decreased.'
If you want to try the method but have concerns about safety, chat with your medical provider and/or a registered dietitian before experimenting on your own.
How to practice 'Hara Hachi Bu' safely
This philosophy can benefit all ages, especially if you struggle with portion control, overeating, or just want to practice mindful eating, Webb says. And even if you have a history of disordered eating, you can still take part in this practice, as long as you check with your doctor and/or dietitian first. Because 'hara hachi bu' applies to every single meal (even the little mid-afternoon snacks), this change will flow more smoothly if you follow Webb and Miyashita’s instructions step by step:
Prepare your environment for a peaceful meal.
'Choose a quiet place with minimal distractions,' Webb says. It doesn’t have to be your dining table—it could be your bedroom if that’s the most calming environment for you. To allow yourself to fully commit to this new process, it can help to disconnect from tech. 'Leave your computer or TV off to avoid further distraction,' Miyashita says. You can also help yourself adapt to smaller meals by choosing smaller dinnerware (think plates, cups, and bowls).
Practice mindfulness to assess your hunger.
Once you’ve hit a six or a seven and start eating, go for non-starchy vegetables first, like broccoli, cauliflower, cucumber, carrots, spinach, tomatoes, zucchini, or bell peppers, to name a few, Miyashita says. Take small bites and chew thoroughly. 'I recommend that you chew more than 15 times with each bite,' she adds. To inspire slow eating, perhaps place your utensils on your plate in between each bite. After finishing the non-starchy vegetables, pause and reference the one to 10 scale.
Stop eating when you're 80 percent full.
Or, in other words, an eight on the fullness scale. If you are used to eating until 100 percent fullness or more, it may take you some time to get used to stopping at 80 percent full, Webb says.
It takes about 15 to 20 minutes for your stomach to signal your brain that you are full,' she adds. 'It can help to eat slowly as this gives your body enough time to recognize these signals.'
Make sure to chew thoroughly before each new bite as this helps your body acknowledge when you are approaching fullness—then, wait to fill up your fork again until your mouth is totally empty.
'It can also be helpful to visually estimate 80 percent of a portion before eating and pausing to assess your hunger throughout the meal—think 80 percent of a hamburger, ⅘ of your soup, or 80 percent of your fettuccine,' Webb says.
Take a mindful pause before going back for seconds.
Contrary to popular belief, abiding by 'hara hachi bu' doesn’t mean you have to eliminate your favorite foods or drastically cut back on portion sizes—it’s more about becoming aware of your body’s cues and taking note of whether or not you’re *truly* full or not each time you eat. There certainly isn’t anything wrong with getting a second plate or eating dessert as long as your body is feeling good.
'If you're still unsure if you're satisfied, wait 15-20 minutes before deciding to eat more,' Webb says.
Keep a food journal.
To document your first few weeks of the 'hara hachi bu' process, keeping a food journal can be helpful, Webb and Miyashita agree. Write down what you ate, the dishes you enjoyed, the ones you didn’t, where you were on the 'food scale,' and how you feel now (physically and emotionally).
You may find that it’s easier to practice the philosophy at certain times of day, or with certain meals, than others. The idea is to write without judgment and use it as a learning exercise. Then, as you expand beyond the trial phase, you’ll be able to look back on your progress and feel pride for how far you’ve come, Miyashita says.
Read next: 5 things to know before getting a bob
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