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Japanese people are, as a whole, very healthy: They have the second-highest life expectancies compared to any other country in the world (the U.S. comes in at number 43) and have an obesity rate of just 3.5 percent, which is one-tenth of America's 35 percent obesity rate.

The reason for Japan's superior health? Their grain-heavy, high-carb diet.

According to a new study by researchers at the National Center for Global Health and Medicine in Tokyo, people who strongly adhere to Japan’s recommended dietary guidelines are 15 percent less likely to die of any cause -- such as cardiovascular disease and stroke -- compared to those who don't adhere well.

Japan’s nutrition guidelines reflect the country's traditional diet, which is high in grains, fish and soybean products, but low in fat. In the U.S., where the tide appears to be turning against grains and toward larger intakes of fat, Japan's contrasting food guidelines are a good reminder that there’s no “correct" way to eat nutritious food -- just different styles that suit different people and cultures best.

Why Japanese people can eat so many grains (and not get fat)

For the study, 80,000 participants answered detailed lifestyle and food questionnaires that determined how well they followed the guidelines, and then researchers tracked their health for 15 years. The top quarter of people who followed the guidelines best had a decreased risk of death from any cause. The researchers controlled for factors like age, sex, BMI, smoking status, total physical activity and history of hypertension, diabetes and dyslipidemia. People with a history of cancer, stroke, heart disease or chronic liver disease were also excluded.

James DiNicolantonio, a cardiovascular research scientist at St. Luke’s Mid America Heart Institute, is a passionate defender of the theory that sugar and carbs are the true cause of obesity and metabolic disease. He also encourages people who want to lose weight to eat more high-fat, high-calorie foods to make them feel more full.

“We can learn a lot about how to be healthy from the Japanese, and it really comes down to 'eat real food' and ‘exercise.’”

But even he notes that the high-carb Japanese diet works, and it’s because of the quality of the food they eat, how little fat they eat, and their activity levels, he explained to HuffPost. DiNicolantonio, who was not involved in the study, says that it's a uniquely Japanese combination of macronutrients that may be saving them from obesity and metabolic disease.

"Combining a high intake of carbohydrates and fat is the perfect storm for obesity," he said. "The Japanese tend to eat high carb (both rice and vegetables) but a low intake of fat."

DiNicolantonio also noted that Japanese people tend to eat lots of seafood, which is rich in healthy omega-3 fatty acids, and they don’t eat as many processed foods.

What’s more is that the average Japanese person walks over 7,000 steps a day, while Americans walk an average of about 5,000 steps per day. Also of note: The health trend to walk 10,000 steps per day actually started in Japan.

Given their diet of whole, unprocessed foods, as well as their active lifestyle, it's no wonder that Japanese people can tolerate more grains than the average American, said DiNicolantonio.

"I think the best takeaway for Americans, when looking at the Japanese, is that if we restrict our intake of refined sugar, industrial seed oils, and increase [our] intake of marine omega-3s, then we might be able to tolerate eating more rice,” he said. “We can learn a lot about how to be healthy from the Japanese, and it really comes down to 'eat real food' and 'exercise.'"

Japan's nutrition guidelines are easy to follow

Japan's 2005 food guidelines represent this culinary history. While Americans enjoyed a pyramid before being presented with a plate, Japan's guidelines are illustrated as a spinning top. Kayo Kuratani, a researcher at the National Center for Global Health and Medicine and one of the study's authors, notes that the graphic is easy to understand and follow. The spinning top is "dish-based," while U.S. guidelines talk mostly about raw ingredients.

"The dish-based method is not only easily understood by those who prepare meals but also by those who eat them," Kuratani told HuffPost. "It is expressed in terms of actual dishes eaten at the table rather than the foods selected or used in meal preparation. This makes it readily understandable even for those who rarely cook."

A figure running around the top represents the need for physical activity. The top's handle is made of a glass of water and tea, and no serving size is recommended for snacks, candy and other beverages (meaning, sugary ones).

BMJ

The largest section of the top is made up of grain dishes like rice, bread, noodles, and rice cakes, recommended for five to seven servings a day. That’s followed by five to six servings of vegetable dishes, then the spinning top narrows further to three to five servings of protein including meat, fish, egg and soy bean dishes.

The final section is split in two: two servings per day each of fruit and milk or dairy products.

What Americans can learn from Japan

Dr. Lydia Bazzano, a nutrition and diabetes researcher at Tulane University, points out that the spinning top guide may be potentially deceptive for Americans. She notes that accompanying written guidelines point out the top is variable according to age, sex and activity level. Highly active young men, for example, can eat more grains than a sedentary woman in her old age.

“Among people who are very physically active, low fat diets with higher grain intake do not necessarily contribute to poor health outcomes and conditions like obesity,” Bazzano said. “However, among persons who are less physically active, higher grain intake, especially refined grain intakes, may contribute to poorer health outcomes and/or obesity.”

Japan’s Ministry of Health, Labour and Welfare did make one major update to the most recent guidelines: Because Japanese people mostly eat white rice as their main grain, and white rice is linked to an increased risk of chronic diseases, the 2010 guidelines recommend that only 50 to 65 percent of a person’s diet should be carbs, and that people should begin to explore whole grains like brown rice, explained Kuratani.

Still, the ideal Japanese diet is a powerful reminder that there’s no one way to achieve a healthy weight and avoid chronic disease. So the next time anyone gives you flack about (gasp!) eating grains for lunch, just let them know that you’re on the Japanese spinning top plan.