I don't think I could be a vegetarian. I have an intolerance to many vegetables, particularly green leafy vegetables that leave me in intestinal agony... largely due to gas build-up but also inflammation and irritation. Plus I don't really get much energy out of vegetables because I don't eat very much food full stop, and you need to eat quite a lot of vegetables to get the full benefit out of them. Seeds and beans, those are all much easier and give me much more energy but I still get the bloating and pain from eating them.
The exceptions that I can eat lots of are starch-based grainy foods such as pasta, rice, oats, and (although not a grain) potato. I can eat lots of those without much difficulty. But for some reason or another, other root vegetables besides potato give me trouble.
I can also eat a lot of fruit, but it depends on what fruit I eat. Bananas give me the same problems that most vegetables do, as do dates and figs. Dates can actually be worse than vegetables at times, especially if I have more than one the pain and bloating can start in a matter of minutes. However, seedy fruit such as pomegranates, or citrus fruits are just fine. Olives are also really good. Citrus fruits actually have a counter-active effect on the pain and bloating, so if I do have a banana or something it'll be followed by a lemon or an orange if possible. I also prefer to have citrus right after meat.
My diet is very meat-based because I don't get pain from meat. I eat a lot of chicken, a fair amount of seafood and a teeny tiny bit of red meat such as beef and lamb once every couple of weeks or so. Because I don't eat much it helps if I eat something very compact in energy.
I remember trying to cut down on meat and eat more veggies. Right after ramadan actually... I was doubled over and almost crying a lot. But that wasn't the first time I noticed I couldn't eat much veg.