proteins and fats take hours to digest. Lim's rice cakes include a little bit of bacon or something just to help with long term energy but unless you are doing a century or something, no fats or proteins you eat during a ride will be providing any energy for you at all. If you ride much over an hour or so, the only foods that make any sense are carbs. Even on a low-carb diet you'll still be doing yourself a favor by exercising hard and eating -carbs- to provide energy for that exercise. The more carbs you eat to provide energy for the harder you ride the more fit you will be. Low/no carbs are fine if you want to play with that diet but assuming the overall point is health and weight loss, hard exercise with carbs trumps less exercise with fewer carbs every time.