All types of rice contain protein, although the amount of protein varies by strain of rice. One cup of cooked long-grain white rice, for example, contains 4.25 grams of protein, while a similar measure of cooked long-grain brown rice contains 5.03 grams.
These amounts of protein are approximately 8 to 10 percent of the daily recommended amount needed in a 2,000-calorie diet. Rice is not sufficient as a sole source of protein, although it is a nutritionally varied food in general. It is the staple food for more than half of the world's population. The high caloric content of rice, approximately 200 calories per one cup cooked, makes it extremely effective at feeding nutritionally-deficient populations.