Grain products can be whole or refined. Whole grains (such as brown rice and oatmeal) contain the entire grain kernel including the bran, germ and endosperm, and are far more nutritious and wholesome than refined grains because the outer layers are a great source of essential nutrients such as fiber, vitamins and minerals. Whole grains are also fiber-rich, which can help you lose weight by making you feel fuller throughout the day to prevent overeating.
Refined grains (such as white rice, white bread and pasta) are processed to remove the bran and germ to become a finer texture. But the process will also remove important nutrients such as B vitamins, fiber, and iron. Refined grains products not only have lesser nutritional value, they are highest in sugar and calories. Refined and non-enriched grain products are just lumps of sugar with plenty of empty calories. They should be avoided as often as possible.
The totality of evidence available from research to date shows there is little evidence that a high consumption of whole grains increases the risk of obesity as refined grains do.
The food we were born to eat: John McDougall at TEDxFremont
"Grain is for Sustaining Life"
- Neijing, The Yellow Emperor's Classics of Internal Medicine