Grains can effect if you have sedentary lifestyle. Cardio needs carbs.
I do cardio but I am still getting the bloatness esp indigestion. 😔
I limit carbs to evening to get good sleep and gut can be an issue. If you can fix gut it will be great to fix bloating etc. but at the same time doctors the good GP can help to fix. Hard to find good GP though. Some naturopaths are good in this field.