Trying to improve my diet

I've been working on improving my diet. I'm suffering from gastrointestinal issues which I believed to be IBS originally but now it's a lot more prevalent and painful, and there's other things occuring. I'd rather not go to the GP. My experience has been they don't understand autism at all.

So I've cut down from eight cans of Coca Cola a day to five, less milkshakes and less orange juice.
I'm also trying to eat more fruit now as well as my diet leaves a lot to be desired, I don't really like eating, it hurts more often than not....I am hoping all of this will lead to my symptoms improving and going and me returning to how I used to be.
I don't know if this is possible but I am putting in a lot of effort.