This sounds brutal. I’m as pro-high-carb fueling as a person can be. I have stated that I have seen no place, ever, for a fat-adaptation-producing diet (ie. low carb high fat), in the past.
I think I will change my tune here. If you are unable to digest sugar, and unable to digest starch, and have to rely on things like apples to get carbs in during endurance performance… I think you might actually be a strong candidate for doing a pretty low-carb high-fat diet.
I’d exhaust the world of options before doing so.
Do you mind explaining how specifically you identified that sugar was a no-go for you? Any sort of testing info would be handy to know.
Working with a registered dietitian who is expert in endurance sport fueling would be a good idea, if feasible.