From all I have read from the experts,,,, you can only digest 300 cals an hour while your riding your bike. That is the metric I have always used. That is to say,,,eat 300 cals an hour and drink 25 oz's of water an hour,,, or more if it's super hot and your sweating profusely. I normally eat bike food on shorter rides. For me,, I really do a great bit better when I eat "real food" only on longer rides (100 miles). Some peps stomachs can't handle eating "real food" while riding. I like PBJ's cheese Payday type candy bars, chocolate milk, fig bars. Easy to digest with a balance of carbs and protien. I like Cytomax powder mix in my bottles and eat gels blocks. Liquid after the blocks help digest them.
My feeling is if you eat more than you can digest by very much you present a conflict with your digestive track wanting to draw blood away from your muscles towards your digestive track so as to digest your food. Thats why I suggest not eating a whole bunch more than the 300 cals unless your body has proven able to digest "real food" ok while your riding.