The digestion process is extremely complex. Many generalizations about food and digestion are made and disputed. On the issue of digestive gasses and flatulence, the Mayo Clinic and other medical giants state that intestinal gasses are, for the most part, caused by the breakdown of sugars in complex carbohydrates, which means foods that are not complex carbohydrates are unlikely—or at least less likely—to cause gas and bloating. Furthermore, the medical science consensus is that consumables with plenty of dietary fiber help move foods through the intestinal tract, which reduces gas development. Therefore, it stands to reason that some foods do not increase gas production and may help reduce it.
Men require 55 grams of protein a day, and women must have at least 45 grams.
Protein sources for non-vegetarians include meat and seafood. Beef, pork and chicken are the most readily available. Game meats such as venison, elk and even goose and pheasant are good sources of gas-free protein. Worldwide, a number of other creatures from ostriches to goats provide meat protein. Note that excess meat in a person's diet is not considered to be healthy primarily because of saturated fat content, so for this reason, leaner meats like skinned chicken and fish are recommended.
Vegetarians need protein too and can obtain plenty of nutritional protein value from nuts like almonds and cashews, the seeds from sunflowers and pumpkins and the pea and peanut legumes. (Other beans are accused of promoting gas.) A range of soy products such as soy milk and dairy products like milk, eggs and cheese are also suitable.
Digestible and Dietary Fiber Sources
Digestible fiber is essentially starch: complex carbohydrates and the guilty gas-causer found in most processed foods (basically the items sold in the grocery store in a box, jar, bag or can with some exceptions). Dietary fiber, sometimes called insoluble fiber, is what the digestion process needs to move food along, thus reducing gas. Many sources of this fiber do not cause gas for most people although this rule has some exceptions.
Beans are excellent dietary fiber, but some people have a gaseous reaction to them. Peas and snap green beans seem to be the least likely to cause gas problems.
Broccoli is probably the best low sugar source of good fiber, along with Brussels sprouts, cabbage, carrots, lettuce and spinach. Eaten raw, these last items have additional health benefits.
Whole grains like oats, bran, rye and wheat are also great sources, but when in baked goods, their effectiveness as a gas deterrent is compromised by the complex carbs baked in with them.
Many fruits are excellent sources of dietary fiber from bananas and coconuts to pears and cherries, as are all the dried fruits, but watch for the heavily sugared fruits like dried cranberries.
Other Non-Complex Carbohydrate Sources
Fats and oils in moderation are actually good for human beings. Saturated fats (meat and dairy fats, primarily) cause high cholesterol problems in many, but vegetable oils, olive oil and peanut oil are unsaturated fats that are not considered to be gas producers, although what one fries in them may be. Vitamins and minerals in supplements are also vital nutritionally to many and are not blamed for producing gas.