Although the average caloric intake of the Chinese is higher than that of Americans (2640 vs. 2360 for adult males), and despite their smaller stature, the Chinese are much thinner than Americans. This may be attributed partially to the greater level of physical activity in rural China, but the evidence also suggests that it is explained partly by the composition of the diet.
The mainstay of the Chinese diet is cereal grain. Carbohydrate intake accounts for 70% of the caloric intake in rural China compared to about 40% in the U.S. More importantly, only 15% of the calories consumed by rural Chinese men comes from fat, compared to almost 40% in the U.S. Although the total amount of protein is more or less comparable in these two populations, the source of the protein is very different: in the U.S. over 70% of the protein is derived from non-fish animal foods [...]