For people trying to follow a low-carb diet in Japan, one big issue is the prevalence of rice. Even if people don't eat rice at every meal, it’s still a major staple. What’s more, the flavor of plain rice itself is highly prized, and telling most people they can't have rice anymore makes the diet too much of a sacrifice.
The best solution for this dilemma is to use lower-carb rice alternatives in dishes where the flavor of the rice is not the star. Any kind of donburi (rice bowl) is a good candidate, as is stew or curry. With curry, it's the mouthfeel of what’s below the curry that’s key. Reserve the real rice for dishes where it really matters, as a treat.
This dish is actually a curry-flavored version of māpō dōfu, since regular Japanese curry, which is based on a flour roux, is quite high in carbohydrates on its own. I've cut down the carbs even further by using green onions instead of regular ones, and leaving out relatively high-carb vegetables like carrots and potatoes. The thickening is provided by a small amount of starch.