I like an old WW exercise, identifying which foods you can control and which ones you can't.
You paid attention to what you were eating and how it made your body/mind feel (kind of like mindfulness or IE) then you would classify foods like a traffic light. Red light foods were ones you couldn't control, yellow were sometimes troublesome, etc. then you could plan better knowing how types of food affect your body.
After awhile you revisit and find that some red light foods might be yellow or vice versa.
The most important thing of all is to keep trying, don't give up, you will find something that works for you and you can live with