When to carb up?

[Susan Otcenas]

But my point is, it isn't the distance, it's the intensity. One of the great things about cycling is exactly that as long as you keep the pace something that's easy for YOU, you can literally ride all day and into the night. When you're doing that, you can stay abreast of nutrition by what you eat and drink along the way. It takes a higher intensity before you start depleting glycogen.

This, exactly.

Our bodies don't actually store all that many calories as glycogen (what, 1500 or so?) and you don't actually want to deplete that, or you will bonk. Sooo, after a couple of hours on the bike, ALL your energy need to come from a combination of what you eat during the ride and stored fat.

Oak is exactly right. At low intensities, you can ride nearly forever. Randonneurs do it all the time. We ride ridiculously long distances over crazy long hours. What we ate the night before or the day before has very very little bearing on how well we ride. At anything more than a few hours, it's the intensity at which you ride, coupled with your fueling during the ride, that will determine your performance on the ride.

(I just finished an 881 mile brevet. I think I ate pizza the night before. I like pizza. Might have had some wine too. And a gin & tonic... Much more important was the 30,000+ calories I ate DURING the ride! )

Mostly, don't overthink it. Eat something you like, something that isn't too heavy or spicy, and don't overeat. Other than that, it doesn't really matter all that much. Really.

Susan