Originally Posted by
big john
What is the purpose of riding fasted? How long is the ride?
When I ride 6 or 7 hours I always eat before and during the ride. Sometimes I have Gatorade during a ride but I don't make a point of it.
A body that always has access to carbohydrates will shut down beta-oxidation and be almost unable to derive energy from fat stores. Exercising while fasting is one way to force the body to uninhibit b-ox and thus make a second energy source available. The result is increased endurance and weight loss, at a cost of some uncomfortable time in the saddle.
This was the entire premise of "carbo loading" back in the '70s. Unfortunately, the exercising while low on carbohydrate intake part got lost in translation and all anyone ever heard about was consuming carbohydrates immediately prior to an event, which was simply to top-off glycogen stores.
I suspect the modern trend towards consuming gels and sweet drinks while riding, as though we are all riding grand tours all the time, is one of the reasons why we see so many cyclists with enormous guts. They turn the excess carbohydrate into fat stores, but that's a dead-end since fat cannot be turned back into carbohydrate (unless you're a plant) and they have effectively shut down their ability to turn fat into energy.