Have the same problem. I deal with it by rarely eating fruit and veg, and my weight has stayed stable for the last three years. Not having a colon doesn't mean you are immune to the laws of thermodynamics sadly, so if you take in more energy than you burn, you will gain weight. That said, are you on any meds associated with weight gain, eg. steroids, psychiatric meds? They don't help.
I don't have any great diet tips, but have you tried making your own veg soup and blending it until it's completely smooth? (Commercial soups usually have too many bits in them.) Or cooking vegetables until they're very soft? For whatever it's worth, well-cooked green beans don't seem to bother me too much. Tomato sauce with a base of onions, etc., however, tends to give me more grief.
If all else fails, you don't need
fruit and vegetables to live. They are good for people with colons because of the fibre and the colon likes them. But you don't have a colon, so you don't have to worry about
that aspect. You can get vitamins and minerals from other food sources, or just pop a multivitamin tablet every day.
As for losing weight, you'll have to calorie count for that one, I'm afraid: eat about
500 cals a day less than you are currently eating for sustainable weight loss. If it's only a little bit of gain, it's probably better to not sweat it however. I'm not as thin as I'd like either, but I can't be bothered torturing myself to lose a few pounds.
Dx Crohn's in June 2000. (Yay )
Tried: 5-ASAs, azathioprine, 6MP, Remicade, methotrexate, Humira, diets.
1st surgery 20/2/13 - subtotal colectomy with end ileostomy.
2nd surgery 10/7/15 - ileorectal anastomosis. Stoma reversed and ileum connected to the rectum.
Current status: Chronic flare. Do I have any other kind?
Current meds: 50mg 6MP; Entyvio (started 3/11/16)