Originally Posted by
Doge
<snip>This is a huge issue with kids that are jacked up on sugar and caffeine pre-race. They take off like being shot out of a cannon and 1 hour later - *poof*.
Finishing use sugar, and caffeine - to go faster.
This is a huge issue with all those who are clueless about nutrition and it's relation to exercise. Not to put too fine a point on it.
A knowledgeable rider will eat 200-400 calories of carbs, depending on time of day, 2-3 hours before a ride and then nothing after that until the ride starts.
Caffeine does not cause bonking. On the contrary, caffeine improves recruitment of fatty acids from stored fat and delays bonking. Which term, as Greg pointed out, refers to using up all one's glycogen, not to a temporary drop in blood sugar, which is what you are referring to.