The Evolution of Japanese Dietary Life Over a Millennium: From Jomon Hunting to the European-Influenced Revolution of the Meiji Restoration

Ancient Japanese diets included plant-based foods, seafood, and wild animals. Plant-based foods included nuts such as acorns, chestnuts, and walnuts; the above-ground parts of plants such as bracken, basil, and angelica; the underground parts of plants such as kudzu and yam; and fruits such as wild grapes. Fish included mackerel, tuna, salmon, and trout. Shellfish included clams and hard clams. Wild animals included wild boar, deer, and rabbits. From the time of hunting and gathering to the early agricultural era, there were no domesticated animals for food. However, due to the large consumption of seafood and wild animals, animal protein was still plentiful.

By the Nara period, fermented foods such as natto, soy sauce, and fermented soybean paste had appeared in Japan. After the introduction of Buddhism, the consumption of meat was prohibited, but the common people still ate animal meat. By the Edo period, eating out (such as soba noodles) had become popular in cities. During the Meiji period, a time of great civilization and enlightenment, the Japanese diet underwent significant changes. The prohibition against eating meat was abolished, and foreign foods and cooking methods were introduced. Workers and students began bringing their own lunchboxes. Eating out was quite common at this time. The diet consisted mainly of starchy foods such as wheat, rice, and potatoes, with a significant amount of vegetables also consumed.

Protein sources such as fish, shellfish, beans, and soy products are secondary. Regarding rice intake, during the Meiji and Taisho periods, the average person consumed nearly 400 grams per day, but by 1988 it had fallen to approximately 200 grams, a decrease of about half. The Japanese diet is primarily composed of rice, fish, soy products, and vegetables, while the intake of livestock products and sugar is lower compared to other countries. The Japanese enjoy eating fresh food. Japan is highly dependent on foreign agricultural products, but exports very little agricultural product or processed food; it mainly exports some seasonings, soy sauce, and a selection of high-end fruits.

Because carbohydrates are inexpensive, national income is inversely proportional to dependence on starchy foods (grains, root vegetables). Although Japan's national income has increased, its dependence on starchy foods remains relatively high compared to other developed countries. Before World War II, the Japanese diet generally had low energy intake, resulting in low rates of heart disease, gout, diabetes, and colorectal cancer. However, insufficient animal protein led to malnutrition, resulting in a higher incidence of tuberculosis. Excessive salt intake also contributed to high rates of hypertension and vascular diseases, and life expectancy was relatively short.

After World War II, Japan faced food shortages, but its diet underwent significant changes starting in 1955. With rapid economic development, Japanese people's fat intake increased dramatically, as did their consumption of fruits, meat, eggs, milk, dairy products, seafood, and sugar, while their intake of tubers relatively decreased. This shift in food consumption greatly improved the nutritional status of the Japanese population. The ratio of protein (P), lipids (F), and carbohydrates (C) in the Japanese diet is now P:F:C = 12:28:60, achieving an ideal balance.

Furthermore, about half of animal protein comes from fish. Protein accounts for 10% to 15% of calories. However, excessive calorie intake has become a major cause of obesity and diabetes, and has also led to an increase in heart disease patients. According to a survey by the Ministry of Health, Labour and Welfare, Japanese people currently consume sufficient amounts of various nutrients, except for calcium and iron. In addition, excessive salt intake is also a problem. Foods can be broadly categorized into plant-based foods and animal-based foods, with smaller amounts of mineral-based foods and chemically synthesized foods.

Plant-based foods include grains, tubers, legumes, vegetables, and fruits. Animal-based foods include meat, dairy products, eggs, fish, and shellfish. Mineral-based foods include salt. Chemically synthesized foods mainly consist of various food additives. Currently, there are 347 approved food additives, more than half of which are chemically synthesized. The main component of grains is starch, accounting for about 70% to 80%, followed by water, protein, fat, and vitamins. However, vitamins are easily lost during refining and processing. Tubers contain more than 70% water and about 25% starch.

Legumes include soy products such as tofu. Soy protein is the primary plant-based protein source in legumes, providing approximately twice the amount of protein found in meat. Legumes are also a good source of lipids. In addition, legumes contain starch and are rich in vitamin B₁. Legumes have high nutritional value. Among vegetables, green and yellow vegetables are particularly rich in vitamins A and C; other vegetables contain more inorganic substances but fewer vitamins. Fruits are a source of inorganic substances (especially calcium). Meat, including poultry, livestock, and fish, is the best source of animal protein.

In addition, pork is high in fat. It is rich in vitamin B₁. Dairy products, including dairy products, are high-quality protein with high nutritional value and contain calcium. Eggs are also a good source of protein. Egg whites are a protein solution; egg yolks are rich in phosphoproteins, phospholipids (such as lecithin), and vitamins. Fish, including fish cakes and other fish products, are also important sources of protein. The Japanese obtain a significant amount of protein from fish. Shellfish and crustaceans, including shrimp and crab, are important sources of protein; clams, cuttlefish, and octopus are mollusks. Mineral foods are primarily salt, which is refined from seawater and rock salt.