Keiko Asakura: What is a Healthy Diet?

2021/12/17

I conduct research that involves recording human diets in detail and considering the relationship between diet and health. When I say that, people might think I cook elaborate meals, but that is not the case. I started researching diet because I want to live as healthily as possible with minimal effort even while busy, and I think many people feel the same way. What I currently strive for is: (1) reducing salt intake, (2) choosing less refined grains as much as possible, and (3) drinking about one cup of low-fat milk a day.

Almost all Japanese people consume too much salt. Excessive salt is a risk factor for conditions such as high blood pressure and stomach cancer, so reducing salt is desirable for most people. However, recommending salt reduction to elderly people who cannot eat enough, thereby further reducing their food intake, would be problematic. Choosing germinated brown rice, partially polished rice, or whole-wheat bread instead of white rice or white bread can increase the intake of dietary fiber and potassium. Dietary fiber is effective in preventing various lifestyle-related diseases, but many Japanese people do not get enough, so it is good to be mindful of its intake. On the other hand, rice contains small amounts of heavy metals that have adverse health effects, and there are reports that these amounts are higher in less refined rice. Milk is a good source of calcium and also contains vitamins and protein. However, it has a high fat content, especially saturated fatty acids, which are a risk factor for cardiovascular disease, so drinking a lot of it is not necessarily good. If low-fat milk is an option, that would be better.

If you're thinking, "In the end, it's just complicated!", you are correct. There is no single food that is absolutely good for your health. A single food contains multiple nutrients, some of which are better to consume more of and others that are better to limit. It is difficult to maintain health by relying on a single food. Conversely, there are multiple foods you can choose to resolve a deficiency (or excess) of a specific nutrient. To get calcium, you can eat komatsuna (Japanese mustard spinach) or tofu. Once you understand this bidirectional nested structure, you will no longer be swayed by the health information overflowing in the streets.

So, what is a healthy diet? Since there are no absolutely good or bad foods and there is always the possibility of some deficiency or excess, it is best to diversify risks by combining various foods. Therefore, terms like "one soup and three dishes" or "30 food items a day" are correct in the sense that they recommend consuming many types of food, but they are difficult to implement. The three items I listed at the beginning are the habits I have arrived at through various research studies as a way to potentially gain the maximum benefit with minimal effort.