What a Diet Suited for Japanese People Should Look Like, from a Leading Expert on Ketogenic Diet Therapy for Cancer

The ketogenic diet is a high-fat, low-carbohydrate dietary therapy with a long history of effectiveness for epilepsy patients. In recent years, there have been reports that the continuation of a ketogenic diet may possibly improve the prognoses of cancer patients, and the diet’s clinical results have been followed closely in Japan as well.

The ketogenic diet is strictly a dietary therapy and is not recommended for healthy people. Nevertheless, by getting to the essence of the ketogenic diet, it is possible to find a diet suited to the constitution of Japanese people.

We spoke with Hagihara Keisuke — a specially appointed professor at the Faculty of Medicine, Osaka University, and the first researcher in Japan to start clinical studies of ketogenic dietary therapy for cancer in 2013 — about the diet and ideal dining conditions necessary for Japanese people to live in good health.

The ketogenic diet’s new potential as a cancer therapy

The ketogenic diet holds promise as a new option for inhibiting the progression of cancer. In fact, therapeutic applications of the ketogenic diet have a long history, dating back to Hippocrates’ treatise on the effects of fasting on epilepsy.

“The ketogenic diet was conceived based on Hippocrates’ treatise as a dietary therapy that was less stressful on the body than fasting. The high-fat, adequate-protein, low-carbohydrate ketogenic diet showed dramatic efficacy in reducing seizures in epilepsy patients.

“The dietary therapy was discontinued for a time with the advancement of epilepsy medications, but it has once again found a role in epilepsy management for those patients whose condition does not respond to medication alone. Ketogenic dietary therapy is provided in Japan, mainly under the supervision of pediatricians.”

Specially Appointed Professor Hagihara Keisuke of Osaka University

The therapeutic effects of the ketogenic diet on non-epileptic patients first came to light around 2010. In 2011, a German group reported clinical results suggesting that a ketogenic diet improved the quality of life (QOL) of terminally ill cancer patients. Since then, the clinical effects of the ketogenic diet have been explored in the U.S. and Europe.

The first clinical study of ketogenic diets for cancer patients in Japan was conducted by the Joint Research Chair of Advanced Hybrid Medicine at Osaka University led by Professor Hagihara.

“Fifty-five cancer patients in clinical stage IV*1 participated in the clinical study, and ultimately 37 patients followed the ketogenic diet regimen that we developed for cancer patients for at least three months.

“The clinical results exceeded expectations, with some patients even going into remission,*2 and the effects at the hospital level were substantive. We are currently preparing to publish a paper on the study.

“We would like to come up with the ultimate ketogenic diet menu based on Japanese cuisine that is tailored to the constitution of Japanese people.”

*1. Clinical stage: The extent of cancer in a patient is divided into stages, from I to IV, according to how far the disease has progressed. Stage IV is the most advanced stage of cancer.
*2. Remission: A state in which no cancer cells are detected in the patient by various tests such as imaging tests. Although it depends on the type of cancer, a patient is considered cured if the cancer does not recur for five years after being in remission.

Fermented foods are an essential component of the ketogenic diet menu based on Japanese cuisine that Professor Hagihara is aiming for. In ketogenic dietary therapy, many people develop constipation because the diet, while it increases protein intake, tends to lack dietary fiber.

The inclusion of fermented foods in the diet is hoped to stimulate intestinal bacteria and regulate bowel movements. Professor Hagihara adds that fermented foods provide mental benefits too.

“For example, eating miso soup puts many people at ease. Perhaps the taste of miso soup brings back memories of pleasant meals from childhood.

“I think eating something that was made with care and effort has a positive effect both mentally and physically. Ultimately, I believe it would be ideal if we could reevaluate our eating habits through the ketogenic diet and return to our native dietary habits that are better suited to Japanese people.”

The importance of restoring traditional dietary habits

Professor Hagihara’s idea of what a diet suited for Japanese people should look like is something he recommends to healthy people and those who want to maintain their health.

“When I ask cancer patients what they eat for breakfast, many of them answer toast. I understand that making toast is the easy option on busy mornings, and I am not saying that you should not eat it. But can we really say that it is suited to the natural constitution of Japanese people?

“If you are born and raised in a different country, you will have eaten different things and it follows that your constitution will be different too. For example, seaweed is a common ingredient in Japan and it contains many nutrients such as vitamins and folic acid. However, we know that the distinctive intestinal microflora* of Japanese people is what breaks down the seaweed and absorbs the nutrients. Whereas when people of other races with different intestinal microflora eat seaweed, they do not absorb the nutrients and do not benefit from the resulting energy.”

* Intestinal microflora refers to the aggregate of all the species of bacteria present in the intestines. It is also called gut microbiota.

“Similarly, it is quite possible that some of the foods claimed to be good in the West may not be beneficial to Japanese people. Since the human body is made from the food we consume, the best diet for Japanese people is what has been eaten in this country for a long time — in other words, the traditional Japanese diet.”

Professor Hagihara warns against unthinkingly adopting Western diets, citing the example of the changes in eating habits of the Inuit people as one of the arguments supporting the effectiveness of the ketogenic diet.

“The Inuit people were known to have an extremely low incidence of cancer when they followed their traditional protein-centric diet consisting of a lot of fish. Their diet was low in carbohydrates and high in fat, very much like a ketogenic diet.

“However, with the influx of Western-style diets after 1910 in Inuit communities, the rate of cancers found in developed countries such as colorectal, lung, breast, and prostate cancers increased among the Inuit people from the 1950s onward.”

It must be said, however, that the ketogenic diet is not a therapy for healthy people to prevent disease. Many people associate ketone bodies with diabetes-causing substances, but ketone bodies are present in every person’s body and function as sources of energy while the body is fasting.

When you have eaten an appropriate amount of food in the evening and fall deeply asleep, it is quite natural in healthy individuals for ketone bodies to increase as you sleep and generally no special controls are needed. Moreover, it must be remembered that following a genuine ketogenic diet, which requires an extremely high fat ratio, is very difficult to do and achieve results on your own.

“The term dietary therapy is often misused to mean whatever people want, perhaps because it seems they can do it easily on their own. It’s unfortunate that people debate the efficacy of the ketogenic diet based on such self-styled diets and believe that it is an accessible health regime. In our research, we provide ketogenic dietary therapy under the direction of certified, experienced nutritionists.

“If healthy individuals wish to reevaluate their eating habits as a way to prevent disease, they should start by returning to traditional Japanese eating habits. Carbohydrates, of course, are an important source of energy, so it is important to consume an adequate amount of carbohydrates.

“Young people who are still growing should eat sufficient rice to match their activity level. People middle-aged or older should eat rice in moderation, adjusting the amount they eat using the size of a final rice course in a kaiseki multi-course dinner as a benchmark.”

Eating carefully prepared meals with someone is important

To maintain a healthy body, both what you eat and the way you eat are important. In households where dishes that require lots of time and effort are served at the dinner table, such as miso soup made from scratch, family conversations tend to be livelier during the meal.

“When you eat while having a conversation, each dish tastes better and you gain emotional stability. It’s my sense that people in families that continue to gather around the dinner table and eat together in a congenial mood are less likely to get sick, and even if they do, they are more likely to recover faster.”

The most important thing to avoid is solitary eating, where one eats alone. Professor Hagihara points out that the problem of solitary eating is greater in households where individuals eat separately than for people who live alone.

“People who live alone may feel lonely when they eat, but since it’s unavoidable in their situations, they can easily convince themselves that this is fine. I often hear that they look forward to eating out with friends once in a while, and that their daily meals are fulfilling in their own way, even if they are alone.

“This is not the case for those who live with their family but eat alone. When you have family members living with you but no one to eat with, the loneliness you feel is so great that you don’t even value the meal itself.”

Today’s world is filled with many different health regimens, and many people try one after another never sticking with any for very long, or else people go to extreme lengths to restrict their diets and end up harming their health.

Professor Hagihara’s message to those searching for a healthy diet that suits them the best is: “Take note of the blue bird right beside you.”

“Like the tale of ‘The Blue Bird’, in which the happiness you believed was so far away is surprisingly close at hand, the secret to a healthy life for Japanese people has been with us for a long time. Reevaluate your diet and start by enjoying Japanese food with your family.”