The Japanese Diet: What is it and How is it Effective?
Article by Charlotte Phillips
The Japanese diet is a highly nutritious diet revolving heavily around unprocessed wholefoods which are rich in important nutrients. This diet has been shown to provide an array of health benefits, all of which will be discussed in this article. Keep reading to discover more about the positive effects of this healthy traditional diet.
What is the Japanese Diet?
The Japanese diet is a whole foods-based diet consisting primarily of fish (both raw and cooked), seafood, and plant-based foods such as steamed vegetables and soybeans. It is low in processed animal protein, refined sugars, and fat: all of which contribute to poorer health, particularly poor cardiovascular health. The diet also includes the consumption of numerous pickled and fermented food products including miso, soy sauce, natto (soybeans), pickled ginger, rice vinegar and tsukemono (i.e., pickles). Professor Koizumi Takeo, a professor at the Tokyo University of Agriculture, explains that “no other country has as many types of fermented foods as Japan” (1). He explains that this is due to Japan’s humid conditions which are suited to reproducing the microorganisms that ferment foods. The Japanese are also keen green tea drinkers, particularly matcha tea which is known to be high in antioxidants such as catechins which are associated with reducing cancer risk, viruses, and heart disease (2).
Not only are there cultural norms on what to eat, but also how to eat. The Japanese are very mindful of the food they are consuming. The Japanese government published a list of healthy eating guidelines, all of which align with a healthy, nutritious diet. For example, reducing highly processed snacks, and consuming vegetable- and grain-based dishes as well consuming plenty of fish, eggs, and meats (3).
What’s the guidance?
The Japanese government have provided the following guidance to the nation:
Enjoy your mealtimes (e.g., be with family)
Establish regular eating hours
Eat well-balanced meals with a staple food, a main and a side dish
Eat plentiful amounts of grains such as rice and other cereals
Combine vegetables, fruits, beans, milk products, and fish into your diet
Avoid excessive consumption of refined sugars, salt, and fat
Maintain a healthy weight and balance your energy intake with exercise
Reduce leftovers and waste through proper cooking and storage methods
Track your daily food intake to monitor your diet and prevent excessive weight gain
What are the health benefits of the Japanese Diet?
Life Expectancy
The Japanese diet offers many health benefits and an overall improved life expectancy, with the average Japanese national living to 84.91 years old (4). Okinawa, an island in the South of Japan, has the highest rate of centenarians worldwide coupled with the lowest risk of age-related diseases including diabetes, cancer, and Alzheimer’s (5,6). This can be partly attributed to the lack of refined and processed foods which are so commonly seen in the Western diet.
Okinawa has a particularly unique diet which is low in calories and fat yet high in carbohydrates. The diet is anchored by root vegetables including sweet potatoes, particularly purple ones, known for their high antioxidant and cholesterol-reducing properties, as well as green and yellow vegetables, soybean foods and medicinal plants and herbs (7). These staple foods are accompanied with small amounts of marine foods and lean meats. The low fat element of the diet is likely to contribute to the remarkable reduced inflammation and low cardiovascular disease observed in this population. Additionally, the high intake of healthy omega-3 fats will contribute to this.
Low Cardiovascular Disease Risk
The Japanese also have remarkably low cardiovascular disease risk which can be easily explained by their dietary patterns i.e., high intakes of unsaturated fats, high intake of oily fish, many plant-based food sources, a low intake of red meat and most importantly, a lack of processed foods. A recent study showed that soy and fish consumption may be a key factor in the significantly reduced cardiovascular disease rate in this developed country (8). The study examined key biomarkers (e.g., HDL-C and folate levels) for cardiovascular disease risk and saw that those with the highest, and most frequent, consumption of soy and fish had the highest levels of the aforementioned biomarkers. Another study assessing the diets of nearly 80,000 Japanese adults demonstrated that those who had the closest adherence to Japanese dietary guidelines had a lower risk of total mortality and, specifically, mortality from cardiovascular disease (e.g., cerebrovascular disease) (9).
Hara Hachi Bu
Aligning with their mindful eating patterns, the Japanese also follow the teachings of the Chinese philosopher, Confucius, who taught the phrase ‘Hara Hachi Bu’. The expression roughly translates to ‘eat until you are eight parts full’. This may explain the impressively low obesity rates in Japan. Japan currently holds one of the lowest obesity rates in the world with only 3.6% of the nation having a BMI >30 (10). When compared to the UK whose obesity rate is currently at an all-time high of 29% (11), it really makes us question why we aren’t all consuming a diet of this nature. Intuitive eating and learning to understand internal hunger cues and knowing when we are full is of paramount importance for our health and wellbeing, as well as helping us to develop a healthy relationship with food.
A beginners guide to the Japanese Diet
Traditionally when following the Japanese diet, meals are centred around one core staple carbohydrate (i.e., steamed rice, udon noodles, or soba). This can then be accompanied with a main of fish, seafood, eggs, lean meat, or tofu, and then a side of vegetables which are often steamed to maintain the highest level of nutrients.
Other popular ingredients include…
Seaweed: full of essential minerals that support our health and research suggests it may reduce blood pressure too (12).
Natto: these fermented soybeans are traditionally consumed at breakfast and are known to have a positive effect on gut health (13).
Miso: this soybean based condiment is consumed in many forms although it is typically used in ‘miso soup’ and frequent consumption of this substance is known to lower blood pressure and heart rate as well as attenuating sympathetic nerve activity (14).
How environmentally friendly is the Japanese Diet?
Nowadays, it is highly important to consider the sustainability of our diets. As a recent article by Nature highlights “the traditional Japanese diet may support a long healthy life and have a low environmental footprint, but many ingredients are now sourced elsewhere, which threatens its sustainability.” Therefore, this may be something to consider when sourcing various ingredients.
Summary
It is evident that the Japanese diet can have rather profound effects on our health:
Lower cardiovascular disease risk
Enhanced quality of life and life expectancy
Increases antioxidants within the body
Reduced obesity levels
Encourages mindful eating
It makes one question why we are not all incorporating this diet, and its guidelines, into our daily lives. Given the associated health benefits, we should all try to adopt some of the key principles of a Japanese-style diet into our routines to help overcome the challenges surrounding eating, particularly with the rise in obesity observed in the UK.
This blog post was written by Charlotte Phillips who is currently studying a Master’s degree in Clinical and Public Health Nutrition at UCL in London. Charlotte holds a Bachelor’s degree in Health and Exercise Science from the University of Bath and is passionate about food, exercise, and the impact of our diets on our wellbeing. Charlotte is also a keen runner and cyclist.
References:
(1) The fermented foods of Tohoku: Highlighting Japan (May 2020). Available at: https://www.gov-online.go.jp/eng/publicity/book/hlj/html/202005/202005_05_en.html (Accessed: November 22, 2022).
(2) Sinija, V.R. and Mishra, H.N., 2008. Green tea: Health benefits. Journal of Nutritional & Environmental Medicine, 17(4), pp.232-242.
(3) Japan: Food and Agriculture Organization of the United Nations. Available at: https://www.fao.org/nutrition/education/food-based-dietary-guidelines/regions/countries/japan/en/ (Accessed: November 22, 2022).
(4) Japan Life Expectancy 1950-2022. MacroTrends. Available at: https://www.macrotrends.net/countries/JPN/japan/life-expectancy
(Accessed: November 22, 2022).
(5) Willcox, D.C., Willcox, B.J., Hsueh, W.C. and Suzuki, M., 2006. Genetic determinants of exceptional human longevity: insights from the Okinawa Centenarian Study. Age, 28(4), pp.313-332.
(6) Willcox, D.C., Scapagnini, G. and Willcox, B.J., 2014. Healthy aging diets other than the Mediterranean: a focus on the Okinawan diet. Mechanisms of ageing and development, 136, pp.148-162.
(7) Willcox, D.C., Scapagnini, G. and Willcox, B.J., 2014. Healthy aging diets other than the Mediterranean: a focus on the Okinawan diet. Mechanisms of ageing and development, 136, pp.148-162.
(8) Yamori, Y., Sagara, M., Arai, Y., Kobayashi, H., Kishimoto, K., Matsuno, I., Mori, H. and Mori, M., 2017. Soy and fish as features of the Japanese diet and cardiovascular disease risks. PLoS One, 12(4), p.e0176039.
(9) Kurotani, K., Akter, S., Kashino, I., Goto, A., Mizoue, T., Noda, M., Sasazuki, S., Sawada, N., Tsugane, S. and Japan Public Health Center based Prospective Study Group, 2016. Quality of diet and mortality among Japanese men and women: Japan Public Health Center based prospective study. bmj, 352.
(10) Health Survey for England - 2019 (2020) NHS choices. NHS. Available at: https://digital.nhs.uk/data-and-information/publications/statistical/health-survey-for-england/2019 (Accessed: November 28, 2022).
(11) Senauer, B. and Gemma, M., 2006. Why is the obesity rate so low in Japan and high in the US? Some possible economic explanations (No. 1710-2016-139983).
(12) Murai, U., Yamagishi, K., Kishida, R. and Iso, H., 2021. Impact of seaweed intake on health. European journal of clinical nutrition, 75(6), pp.877-889.
(13) Kanai, T., Matsuoka, K., Naganuma, M., Hayashi, A. and Hisamatsu, T., 2014. Diet, microbiota, and inflammatory bowel disease: lessons from Japanese foods. The Korean journal of internal medicine, 29(4), p.409.
(14) Ito, K., 2020. Review of the health benefits of habitual consumption of miso soup: focus on the effects on sympathetic nerve activity, blood pressure, and heart rate. Environmental Health and Preventive Medicine, 25(1), pp.1-9.