I've read that it works like this: The fewer times you eat, the more fat you store, since the body has to work a long time without any input.
Sumo fighters train actually a lot, really a lot of sport, and eat just once a day, a broth that is called chanko-nabe (which is actually quite a healthy dish, not as much calories as you would expect). That's how the build a strong body covered in a thick layer of fat.
On the other hand:
Among the great apes, we are the ones that are better developed for fasting and starving, and that is because we store more fat than our relatives. Chimps and Gorillas have hardly any fat, and that's because they are eating almost all the time, pickling around (especially the gorillas). When you see a Gorilla's abdomen, it's actually hard (it's because of the greatly enlarged bowels, in order to ferment the plants they feed on), no layer of fat.
I read that this is because we, humans, had to adapt to a savannah environment, where food was scarce and hard to get, whereas chimps (our closest relatives) where in the fair part of the mountain ridge, with rainforest, and food was all around.
If you think about it, this is very logic. If the apes are eating constantly, there is no need for the body to store any fat, since the next sugar/nutrient input is right next to you, or close by. If you fast for a day, or eat very few times, the body will store as much fat as it can, since "he" doesn't know for how long will it have to go without food