In 2019 I spent 3 weeks traveling around Japan with my brother, eating my bodyweight in sushi and sake, dodging typhoons and immersing myself in a culture very different from my own. Simultaneously, Dame Sally Davies urged the UK government to take measures to fight the nation’s child obesity problem in her leaving report that was published earlier that month. Among other things, she pleas to ban eating on public transport, restrictions on fast food marketing for kids and setting calorie caps for take away meals. 

Critics accused her of promoting a “nanny state” and how it shouldn’t be illegal to eat a sandwich on a train. This personally enrages me. Politicians are talking about protecting freedom of choice while they know very well that all they are doing is protecting the interests of the food industry. The industry is doing so much already to make their products healthier. Great that they’ve sold 57 million kg sugar less than in 2015 (mainly to avoid the UK sugar tax anyways), but the reality is that it hasn’t helped to fix the issue. Kids are still getting sick and overweight at ever younger ages. We need real solutions that may interfere with our freedom but make a difference. That this is possible and works is what a country like Japan shows.

The modern Japanese diet isn’t even that healthy

The Japanese diet isn’t particularly healthy in my experience. They eat a lot of fish which can be healthy, but fresh fruit and vegetables are expensive (£10 for some grapes and at least £3 for an apple, no joke) and often not served when you eat out. Many places don’t have vegetarian or vegan options. We counted 2 vegan restaurants on our 3 week trip. They eat fish or meat and white rice with miso soup. Not much else. Often food is also fried (that Mozuku seaweed tempura tho!) or very processed. The traditional Japanese diet contained more vegetables and less meat and fish as Buddhism discouraged it but the country is not immune to changing traditions and the influence of Western diet. The consumption of meat and dietary fat has gone up in the past 30 years but Japan still has the lowest rates of obesity on the planet. 4.2% of adults are obese as opposed to 26.2% in the UK and an astonishing 39.8% in the US. Yes, I had to fact check this number across multiple sources to make sure, but almost 40% of the US adult population is not just a tad chubby, but obese, meaning they have a BMI of over 30.

Obesity isn’t caused or cured by one single factor, the fact that food is very expensive in Japan and that the Japanese are more active (not because they go to the gym, but because they walk more and driving a car is expensive) also plays a role. However, there are 2 things I’ve noticed in their eating behaviour and food environment that we can learn from.

Fish market in Japan
Fish market in Japan

We are all mindless eaters

Each of us makes more than 200 nearly subconscious food choices every day. (..) We’re nudged more by our eating environment than by our deliberate choices. Most of these subtle nudges, such as the size of our cereal bowl or the distance of the candy dish – push us to eat too much. – Brian Wansink PhD

Food environment that discourages grazing

Eating behaviour is driven by many different factors, not just by physiological cues such as feeling hungry, but maybe even more so by unconscious ones. We think we have control over our eating behaviour but how often do you find yourself eating something, not because you were hungry, but because there’s food in front of you? The majority of food choices such as how much or when to eat are made unconsciously. Controlling your food environment is key to making the healthy decision on autopilot.

Japanese people love food, there’s restaurants, izakaya’s (Japanese pubs), markets and food everywhere. But without the grazing culture that we have in the UK. They eat 3 meals per day and don’t snack. Or at least, not in public. You cannot eat/drink in public spaces because it’s considered rude to eat in front of people who aren’t eating. Even if you go to a foodmarket and buy something to eat, you’re asked not to walk around and eat, but instead sit in a designated area (often a corner, out of sight) to do so. How different are we living our lives in London? Eating on the go and constant snacking is the norm. Seeing people eat encourages eating even if you weren’t planning to. 

As Stephan Guyenet explains in his book “the Hungry Brain” our brain is constantly looking for easy calories. The more effort it takes to eat something, the less inclined we are to do so. Having to take time to sit down and eat in a hidden corner, increases the barrier to eat. Something as simple as removing snacks from your desk to a cupboard, so you have to get up and get it, will reduce your snacking behaviour. Research has repeatedly shown this and it’s the same principle here. Banning eating in public transport will increase the barrier to eat, you’d actually need to make time and go somewhere else to have your snack. As we are all time poor people, the result will often be to skip the snack. 

Eating behaviour that encourages portion control

I am used to eating a lot of volume and I add rocket and watery vegetables to pretty much every meal I eat. The first week I really had to get used to Japanese portion sizes. Food is never served on one plate, instead you get multiple smaller dishes. The idea of starter, main and dessert is completely alien to them. Partially this can be explained by the fact that the Japanese are a fair bit smaller than me and my brother with our 1.80 m and 1.90 m, so they’d need less food as well but it doesn’t account for all of the difference. 

Portion control is also reflected in their practice: “hara hachi bun me” it means to eat until you are 80% full. Calorie restriction is therefore ingrained in their culture. This extends to western foods sold in Japan as well. The portion of fries from western fast food chains are smaller than the UK sizes and it is still possible to get a “short” size (8 ounce/236 mL) coffee at Starbucks, in London the smallest size is “tall”(12 ounce/355 mL). In the west we are not raised to listen to our bodies, we are all raised with the idea to finish what’s on your plate. And whatever is on there, has increased. Davies’ report shows portion sizes have increased massively over the past 30 years and bigger portion sizes encourage overeating. The size of a pizza has increased by 53%, serving size of a packet of crisps by 50% and the average take away fish and chips meal contains 1652 kcal these days. There’s really no reason we shouldn’t limit companies in doing this. No kid needs to eat their daily calorie requirement in one single meal.



Japanese practice to eat until you are 80% full. It may in part explain why the Japanese, although declining in recent years, still have one of the highest life expectancies in the world.

Take home message

Obesity is a complex problem and solutions involve more than banning eating in public, restrictions on food advertising and portion sizes. We cannot control the choices people make at home and I think the lack of education on healthy food in schools and the workplace is also a problem. Nobody gets fat on purpose, but controlling eating behaviour is often more about controlling your food environment than anything else. These measures will help moving forward to create a healthier food environment in public at least. It won’t create a nanny state and our government should stop crying about “sin taxes” (talking to you Boris) and implement regulations that work. Banning smoking in public places also wasn’t a popular measure at first but good luck finding someone who thinks it’s ok to smoke on a train now. As always regulation is behind science, until the UK government catches up, you can apply these simple rules to your own life if you are struggling to keep your weight in check. Act like the Japanese: don’t eat in public, take the time to sit down for your meals and snacks and eat until you’re 80% full.


Davies, S. (2019) Time to Solve Childhood Obesity. An Independent Report by the Chief Medical Officer. Access at:

Guyenet, S. J. (2017). The Hungry Brain: Outsmarting the Instincts That Make Us Overeat . Macmillan.

Hales, C.M., Carroll, M.D., Fryar, C.D., and Ogden, C.L. (2017). Prevalence of Obesity Among Adults and Youth: United States, 2015–2016. NCHS Data Brief, No. 288. Access through:

Livingstone, M.B.E. and Pourshahidi, L.K., (2014). Portion size and obesity. Advances in nutrition, 5(6), pp.829-834.

Matsuzawa, Y., (2018). Specific health guidance, the nationwide lifestyle intervention program targeting metabolic syndrome, seems to be successful in Japan. Journal of atherosclerosis and thrombosis, p.ED092.

Senauer, B. and Gemma, M., (2006). Why Is the Obesity Rate So Low in Japan and High in the U.S.? Some Possible Economic Explanations (nr. 1710-2016-139983).

Wansink, B. (2016). Slim by Design; mindless eating solutions for everyday life. London: Hay House UK.

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