It might sound like bad advice, but for Japanese men, eating a high-carb diet could actually be a good thing—only, it depends on the type of carb. Because eating too much of the wrong ones could have dire consequences.
These are the findings reported by Professor Chisato Nagata and colleagues from the Gifu University Graduate School of Medicine in Japan—recipients of the inaugural British Journal of Nutrition Paper of the Year award.
Their paper, published in volume 122, issue 7 of BJN, describes a subset of results from the Takayama Study. The study was launched in 1992 to link dietary and lifestyle factors to morbidity from cancer and other diseases. Participants filled out a questionnaire at baseline on how frequently they ate various foods.
Professor Nagata and her team estimated the intake of carbohydrates, breaking them down by type: starches, which were found to derive mainly from rice and cereals, and sugars such as glucose, fructose, maltose, and lactose, which were most commonly consumed in the form of sweetened beverages.
Sixteen years later, they found that in men, a higher intake of starch was associated with a significantly decreased risk of total mortality. A higher intake of total sugar, however, was associated with a significantly increased risk.
The findings suggest that a high-starch, low-sugar diet could favor longevity in Japanese men.
No such link was observed in women.
It’s possible that some unknown factors could have influenced the team’s findings. But they are supported by other studies that have found total sugar intake to be similarly detrimental.
Professor Nagata and her colleagues note that additional studies are needed to clarify the link between carbohydrates and mortality.