I had serious stomach problems about 2 months ago. I tried the vegan diet, and it felt ok for a few days, but then the same old problems came back. I switched to the PHD (perfect health diet), which is a version of the popular paleo diet, or caveman diet, and now everything is fine:) The diet is basically:
Eat - 1 lb safe starches (potatoes, white rice, etc); 3 pieces of fruit; 1 lb vegetables; 1 lb meat or fish; low omega 6 oils (coconut oil, butter, etc)
Don't Eat - Grains (except white rice); Legumes (except grees beans and peas); added sugars or foods with added fructose; high omega 6 oils (corn oil, sunflower oil, etc)
Looking back on it now, maybe if I had avoided grains and legumes the vegan diet would have worked. But I would have to eat a lot more, in weight and volume, to get enough calories to live, so I prefer the caveman diet.
Which do you prefer?