Originally Posted by
UnCruel
Yeah, that's the point. Calories I'm burning are calories I need to complete the ride. If I don't eat it, then it has to come from somewhere else. Maybe my metabolism is unusual, but my body just doesn't have the energy reserves to get me through a ride that long without taking in some carbs, and/or it can't convert fat to energy fast enough to keep me going. I have really struggled on longer rides, and it's clearly because I have failed to supply myself with enough or the right kind of energy sources along the way. However, I don't think I'm that unusual in this regard. Everything I've been reading about it suggests that 60g per hour is what a rider my weight should be taking in for the kind of riding I'm doing (not racing, which requires even more).
Unless you've got some kind of medical condition, I don't think that you should really *need* constant fueling at ~3hrs of low or even moderate intensity; your body should have a couple thousand calories on tap via glycogen stores. If you can, start doing your shorter rides in the morning while fasted, and at low-ish intensity (Zone 2) to get your body (and mind) used to the load, while working off of reserves. I can wake up and hammer out 62miles/100km with nothing but water (beyond that, my output starts to droop unless I have some snackies).
Oh, and pay attention to your water intake. I think that a lot of people that "bonk" on the bike are dehydrated, rather than running out of fuel.