Whole grains such as black rice contain more insoluble dietary fiber than other grains, and are less suitable for people with stomach problems or those with irritable bowel syndrome. 1. black rice and other whole grains tend to be richer in insoluble dietary fiber, per 100g of black rice contains 3.9g of dietary fiber, while per 100g of rice contains only 0.6g. insoluble dietary fiber in the stomach is not easy to be digested, digestive function of the normal consumption of people with a strong sense of satiety, and digestive function of the consumption of people with digestive problems are prone to flatulence, acid reflux situation. 2. The dietary fiber in black rice is fermented by intestinal bacteria in the colorectum, which will produce some gas to stimulate intestinal peristalsis. If people with irritable bowel syndrome consume it, they are more likely to have diarrhea, abdominal pain, bloating and other problems.