Obentos manager Justin Hao says health-minded customers choose from vegetarian and meat-centered dishes to fit their exercise plans.[Photo by Guan Xin/China Daily]

Numbers game

A typical meal, a bento box with sake-steamed chicken in ginger ponzu sauce, lotus root, egg roll, kale gomaae and spicy bean sprouts, runs 58 yuan ($8.80) before the discount. It adds up to 322 calories, with 39 grams of protein, 11 grams of fat and 18 grams of carbs. You can do the math on every meal from Obentos as it includes this data on all menu items, listed in categories from breakfasts and bento boxes, salads and grains, noodles and soups to fruit juices and smoothies. A dumbell icon indicates the item is "high-protein", while plates that are "light", "low-carb", "low fat", "omega 3" and "vegetarian" are also flagged.

Similarly, Beijing's Tribe restaurant has recently parlayed an award-winning healthy menu into Tribe Nutrition, a small storefront next to the B-Active gym in Sanlitun Soho. The gym offers fitness programs paired with a daily menu from the restaurant.

Routine is important, says Living Bigg's Wang.

"The trick for me is to be strict about food Monday to Thursday, then enjoy myself - without going crazy - over the weekend. That means eating pretty much what I want Friday to Sunday, but always in moderation."