Sometimes diet helps, sometimes it makes no difference at all.There is no one size fits all diet.Some things to look out for.If you tend to diarrhea, sometimes too much starchy foods can be a problem, and a lower carb diet can help.Others with diarrhea tend to have problems mostly with greasy/fatty foods and have to limit that more than starch.High sorbitol foods (some low carb processed food as well as raw stone fruits (anything with a pit like a peach), apples and pears and cherries can loosen stools. But if you are constipated you might want to eat those fruits.Some people with gas and diarrhea have problems with lactose or fructoes, but that is not universally true, some people get that from starches.Alcohol and caffiene bother some people.Small frequent meals (sometimes no matter what they are made of) may help more than limiting this food or that food.You may also need to look at how much fiber you eat and see if there is a level that helps (may be higher or lower than what you typically eat now).For a lot of people they spend all their time on diet modification and get very stressed out and fearful of food when it makes no difference and the stress and fear is worse for them than any food would ever be.You may also have to look at physical stressors other than food. Are you sleeping well, exercising enough but not too much, weather conditions (which you can't do much about, but if you know spending a lot of time in the heat or cold sets you off you can be prepared).