Brown rice and white rice have similar amounts of calories, carbohydrates, and protein, although many types of brown rice contain more fat than white rice. The difference between the two forms of rice lies in processing and nutritional content. If only the outermost layer of a grain of rice (the husk) is removed, the result is brown rice. If the bran layer underneath and the endosperm are removed, the result is white rice. Several vitamins and dietary minerals are lost in this removal and the subsequent polishing process. A part of these missing nutrients, such as Vitamin B1, Vitamin B3, and iron are sometimes added back into the white rice making it "enriched", as food suppliers in the US are required to do by the Food and Drug Administration (FDA). One mineral that is not added back into white rice is magnesium; one cup (195 grams) of cooked long grain brown rice contains 84 mg of magnesium while one cup of white rice contains 19 mg.
When the bran layer is removed to make white rice, the oil in the bran is also removed. Rice bran oil may help lower LDL cholesterol.
Among other key sources of nutrition lost are small amounts of fatty acids and fiber.
In addition to having greater nutritional value, brown rice is also said to be less constipating than white rice. Although this effect also depends on natural adaptation to the product by its users and whether or not the rice has been washed prior to cooking, brown rice generally allows better digestion[