Low carb is apparently trending in Japan (as well):
Japan Times: Japanese Go out on a Limb for Health (but Not for Love)Now trending in the Japanese 健康 ブーム (kenkō būmu, health boom) are 体幹 (taikan, body core) training and 糖質制限 (tōshitsu seigen, limiting sugar). Although the Japanese are among the slimmest people on Earth (according to the World Health Organization, Japan's obesity rate is 4.5 percent, ranking 166th in the world), everyone longs to get thinner.
Right now, we believe that copious amounts of 運動 (undō, exercise) and limiting sugar intake is the ticket, which for many people translates to running at least three times a week and ditching 炭水化物 (tansuikabutsu, carbohydrates).
More people are avoiding 白い食べ物 (shiroi tabemono, white-colored foods), namely 白米 (hakumai , white rice), 白パン (shiropan, white bread) and うどん (udon, wheat noodles), widely considered the three staples of the Japanese diet.