This is definitely the oddest sport I've ever heard of.
P.S. Stephan Guyenet has a related post here: "Weight Gain and Weight Loss in a Traditional African Society":
"It lasts two months, during which they are overfed on sorghum, milk, fish and vegetables (mostly sorghum, but with an increased ration of milk as well). They eat beyond the point of nausea, day and night, and expend as little energy as possible. Calorie intake exceeds 8,000 kcal per day. According to two detailed studies of nine Massas, by the end of Guru Walla, they had gained about 37 pounds (17 kg), mostly as fat..."