I have GP and one thing for sure that you cannot eat salad nor can you eat any raw veggies or fruit. You can eat bananas, peeled apples, canned peaches made into a smoothie. No wheat, rye or any breads other than white bread. You can have smooth creamy peanut butter (if you make your smoothie, throw in a big spoon of creamy peanut butter to give you more protein. You can have plant butter, almond milk and ice creams that are non dairy. No dairy products.
Baked fish and chicken. Nothing fried unless you coat it in gluten free flour or meal and cook in plant butter. Put a lid on if you fry in this method, add a bit of water and let it steam until soft.
When your symptoms lessen, you can try gluten. I have also been sugar free for 3 years, using only Stevia.
You can have baked white potatoes with plant butter and baked sweet potatoes with plant butter, Truvia (Stevia’s name for brown sugar) and some cinnamon.
Eat French style green beans ( no bean in it) canned carrots, canned peaches in light syrup and canned apples as long as no peeling on them. Do this for a year and you should have much less pain.