Plenus “kome” Academy

Why Japanese Food is Good for Health

Kasato Maru – Japanese Overseas Migration Museum - JICA Yokohama

Kasato Maru
Japanese Overseas Migration Museum - JICA Yokohama

Not only do the Japanese have a high average life expectancy, but they also have some of the healthiest, most independent long-lived people in the world. Once could say that this longevity is backed by the Japanese diet, while takes advantage of the rich variety of ingredients found in the seas, mountains, and fields of Japan.

Over many years, human beings have adapted to the dietary environments of the regions where they live. Let’s take a look at how people have been affected by these dietary environments and the places they were born and brought up in.

Examples from Immigrants to Hawaii and Brazil

Compared to Caucasian people, Japanese people tend to develop hardening of the arteries later in life. However, it is reported that second-generation Japanese raised in Hawaii develop this condition earlier in life, and by the third generation, the difference to Caucasian people almost completely vanishes. Research into the rates of cancer development also show that from the second generation, there is a greater number of sufferers. It is speculated that this is because unlike their parents’ generation, the children and grandchildren of those immigrants have synchronized to the dietary lifestyles of where they live.

In the case of Americans of Japanese descent, cancer rates increased, and in Brazil, the switch to a meat-focused diet saw an increase in incidence of heart attacks, with statistics showing at least a 10-year drop in average life expectancy.

HAWAIICentral Japanese Conference 1903 Konosuke Otsuki Material (Japanese Overseas Migration Museum - JICA Yokohama), BRAZIL:Upkeep of Three-Year-Tree Coffee Plantation Held by Takeshita Photography Studio, Susaki, Kochi Prefecture.

As there are multiple research reports showing that the adoption of Western dietary habits by immigrants of Japanese descent increases the rate of lifestyle diseases and shortens life expectancy, people have come to believe that Japanese diets are more healthy and lead to longer lives.

Changes in Food Culture Created by Climate and Environment

The mother’s milk of mammals contains lactose. Baby mammals break down this lactose into glucose and galactose to absorb it, using a catabolic enzyme called lactase. However, after the weaning period, they lose the ability to secrete lactase within the body, and become unable to break down lactose. This is why a considerable number of Japanese suffer effects such as diarrhea or upset stomachs as a result of drinking milk.

However, Europeans continue to be able to secrete lactase within the body even as adults. It is believed that their ancestors’ bodies adapted to living in cold environments where it was difficult to grow grains, which forced them to adopt a dietary lifestyle that depended on dairy products and meat to survive.
Proportion of adults incapable of digesting lactose among indigenous peoples of the Old World (excluding America)

Proportion of adults incapable of digesting lactose among indigenous peoples of the Old World (excluding America) Source : Global map of lactose intolerance frequencies

One could say that human bodies adapt to the food of the region where they live, and continue to change as a result. Even European research to test the effects of the Mediterranean diet, well-known for its healthy qualities, has shown that there are differences in its effectiveness per country.

Source : The NU-AGE Project

Rice Column3 Yojo Kun

The Edo-period Health Manual Yojo Kun

Yojo Kun is a health manual
(a healthcare regimen) authored by the Confucian scholar Ekiken Kaibara during the Edo period (1603–1868). While the average life expectancy during this period was around 40 years old, Kaibara wrote the manual at the ripe old age of 83. To this day, Yojo Kun contains numerous messages that are still valid to this day, serving as a lifestyle manual that provides not only a healthcare regimen for the body, but also for the mind.

Yojo Kun edited by Kaibara Atsunobu – Oe Library
Tokyo Kasei Gakuin University

On Mental Health

“The first step to health is cultivation of one’s mind. Keep the heart from suffering and keep the spirit free from harm by being calm and peaceful, refraining from anger and greed, and restraining melancholy and worry—these are important methods to cultivating one’s mind.” (Volume 1, 9)

On Dietary Lifestyle

“In all meals, favor plain, lightly-flavored things. One must not eat many rich, fatty foods.” (Volume 3, 6); “Eating until one is full will cause bitter misfortune.” (Volume 3, 8); “By eating sufficient amounts of foods with each of the five flavors, one can avoid illness. Even if one eats a variety of meats or vegetables, continuing to eat the same things will cause those foods to stagnate in the body and inflict harm.” (Volume 3, 9)

Yojo Kun mentions “illness starts from the mouth,” “eating and drinking in moderation,” and “eating and drinking until eight-tenths full” (idiomatically, also eating and drinking in moderation) on numerous occasions when admonishing against overeating, making it clear that these are important principles. Modern dietary manuals also have their foundations in these principles.

On Gratitude for Food

“There are five thoughts when eating.” (Volume 3, 18)

The five thoughts:
  1. Gratitude to the person who provided the food
  2. Thoughts for the labor of the people connected to the food
  3. Happiness at being able to eat something that tastes good, despite one’s own lack of aptitude, virtue, or outstanding actions or deeds
  4. Happiness at being able to eat enough, while others starve
  5. Thoughts for one’s ancient ancestors, who unable to grow staple crops, evaded starvation by eating fruits, berries, and roots

Portrait of Ekiken Kaibara (detail)
– Kaibara Family Archive

These five thoughts are present in the phrases itadakimasu (“I humbly receive”) and gochisosama desu (“It was a treat”), which the Japanese say before and after a meal respectively, and perhaps they will serve to help understand and pass on Japanese dietary culture.

* Source: Yojo Kun Zengendaigo-yaku (“Yojo Kun – Full Modern Language Translation”), as translated by Tomonobu Ito

Was the Japanese Diet in Its Ideal State c.1975?

The Japanese diet receives global attention, as it is seen as good for one’s health. There are various kinds of research taking place to examine what kinds of positive effects it has on the body.

Here, rather than looking at the nutritional value of the individual ingredients of the Japanese diet, we’ll be looking at the health benefits of the Japanese diet by evaluating diets in their entirety.

Test Comparison of Japanese and American Diets

In the same way that Japan has the Japanese diet, other countries each have their own traditional diets. In an experiment to compare the Japanese and American diets using rats, it was found that the Japanese diet has the health benefits of energizing carbohydrate/lipid metabolisms, low stress on organs and low oxidative stress, and excretion of cholesterol. Because there was no conspicuous difference in PFC (protein, fat, and carbohydrates) balance between the Japanese and American diets, it is thought that the reason why Japanese diets had the above benefits may be due to qualitative differences, for example what kinds of ingredients were consumed.

Japanese Diet
  • Rice
  • Dried daikon strips and kombu with dressing
  • Pork fried with ginger
  • Miso soup
American Diet
  • Bread
  • Pork and beans
  • Salad
  • Desert
  • Coffee
  • Cola

* The Japanese diet was based on the 1999 National Nutrition Survey, while the American diet was based on the 1996 USDA Continuing Survey of Food Intakes by Individuals. These were used as references to create breakfast, lunch, and dinner menus for a week each. The above shows part of the dinner menus.

Test Comparisons of Japanese Diets by Time Period

While the Japanese diet has been inherited as a tradition, it has still changed as time passed. In an experiment to compare current and past Japanese diets using mice, it was found that the 1975 diet had the notable features of reducing the risk of obesity, fatty liver, and diabetes, as well as anti-aging and longevity-extending effects. There were no conspicuous differences in the nutritional composition for the diet from each period, so it is inferred that, like the comparison between Japanese and American diets, these features arise from qualitative differences.

1975-Period Japanese Diet Menu

When browsing with smartphone,this table can be side-scrolling.

1st Day 2st Day 3st Day 4st Day 5st Day 6st Day 7st Day
Salt-grilled salmon
Miso soup with
Chinese cabbage
and bean sprouts
Raisin bun
Sausage and
cabbage sauté
Dried horse mackerel
komatsuna (Japanese
mustard spinach) stew
Scarlet runner bean
amani (sweet pot)
Miso soup with eggplant
Bacon and egg
Fruit yogurt
Fried egg
Miso soup with cabbage
and abura-age
(deep-fried tofu)
Boiled egg
Broccoli and tuna salad
Asari clam and cabbage
steamed with sake
Miso soup with tofu
and abura-age
Lunch Kitsune udon
(udon soup with
deep-fried tofu)
Chinese fried rice
Seaweed soup
Fruit mitsumame
(mixture of fruit, beans,
etc. with syrup)
Sweet potato rice
Koya-dofu no fukumeni
(freeze-dried tofu boiled
in syrup)
Pork miso soup
Oyakodon (egg and
chicken on rice)
Kohaku namasu
(red and white salad)
Eggplant fried with
minced meat
Simmered hijiki
Consommé soup
Dinner Rice
(meat and potato stew)
Vinegared mozuku
Clear soup with
cabbage and egg
Chikuzenni chicken stew
Hiya-yakko (chilled tofu)
Miso soup with spinach
and abura-age
Creamed stew
Boiled greens with
Chinese cabbage and
dried shrimp
Cucumber and hijiki
seaweed with dressing
Mackerel simmered
in miso
Soybeans boiled
with diced vegetables
Clear soup with Chinese
cabbage and seaweed
Horse mackerel
marinated in spicy sauce
Miso dengaku
(baked tofu)
Clear soup with pumpkin
and komatsuna
Flounder boiled with
soy sauce and sugar
Fried and simmered
okara (tofu leftovers)
Miso soup with taro
and daikon
Simmered satsuma-age
fishcake and
Chinese cabbage
Shira-ae (vegetables
dressed with tofu and
white sesame)

* Japanese menus, each for a week’s meals, were created to represent 2005, 1990, 1975, and 1960,
based on National Nutrition Surveys and other surveys of national health and nutrition.

One could say that this period was a time when the Japanese diet had started to Westernize slightly. Let’s take a look at five features of the 1975 Japanese diet, which had evolved to become the healthiest of the four diets chosen.


Small amounts of various ingredients. At least three items of main and side dishes combined.


Prioritization of simmered, steamed, and raw foods. Following these, boiled and roasted/broiled foods, then deep-fried and fried foods.


Strong intake of soy products, seafood, vegetables (including pickles), fruit, seaweed, mushrooms, and green tea. Moderate amounts of egg, dairy, and meat.


Careful use of dashi and fermented seasonings (soy sauce, miso, vinegar, mirin, sake) and limited intake of sugar and salt.


Eating various foods based on the ichiju-sansai combination, with rice as the centerpiece.

Introducing the Supervisors of “Rice and Health”

“The Basics of Rice as a Food,” “Rice, the Heart of Japanese Food,” and “Rice Columns 1–3”

Yoko Okubo

Born 1943. Chairwoman of the Japan Society of Home Economics – Division of Food Culture, and Director of Washoku Japan. Born in Gunma Prefecture. Graduated from Jissen Women's University, Faculty of Letters and Home Economics. Doctor of Food Science and Nutrition. Specialist in cuisine science and food culture theory.

“Why Japanese Food is Good for Health”

Tsuyoshi Tsuzuki

Born 1975. Associate Professor, Tohoku University Graduate School of Agricultural Science. Born in Toyota, Aichi Prefecture. Completed a doctoral degree at Tohoku University Graduate School of Agricultural Science. Assistant at Miyagi University School of Food, Agricultural and Environmental Sciences, then assistant professor before assuming current role in 2008. Specializes in the study of functional foods.