The problem with gassiness can often be found with beans. They should not be excluded from the diet, however, because they are great sources of protein, calcium and iron, among other nutrients. But if you are new to beans, it is good to have them in small portions and always very well cooked. A well-cooked bean is very soft, with no hint of crunchiness. As time goes on, your digestive tract adjusts, so a bean that may cause a problem today may be better tolerated later on.
Also, cruciferous vegetables can cause indigestion for some people. The answer is simply to cook them well. This group includes broccoli, cauliflower, brussels sprouts, kale and cabbage, among others. It is common for people to eat them raw or only slightly cooked, but they can easily cause gassiness or bloating. Cook them well, and the problem usually disappears. Later on, you can experiment again with less-cooked vegetables.
On the good side, rice is very easily digested, and a great food to emphasize. Brown rice is best. Also, cooked green, yellow, and orange vegetables are very easily digested. Fruits vary. Some people do very well with raw fruit; others
have more difficulty at first. If you are new to any particular fruit, you might have smaller servings at first, then gradually increase.