Originally Posted by MoAlpha

Agree with all of the above and well stated.

Now explain this to me: I am a skinny little gink who, rides 10-15 hrs a week, eats a relatively low carb diet diet (what wife prefers) and hasn’t bonked on the bike in decades. However, if I put in a six hour day of easy sailing with the spouse, by the time we get to the dock or anchorage, I am nearly always starting to bonk (I know the feeling) and after I get the anchor down and the most important things semi-squared away, I simply collapse, to be revived only by copious carbs and the immediate promise of gin and tonic. An hour later, I’m fine. I have tried to time Clif Bars throughout the day and it helps a bit. Notably, I never crash metabolically on ocean races, where the watches are only 3 or 4 hrs and regular old sleepiness is the big problem.

I think I need the continuous muscle activity from cycling to stay up, but I don’t understand how that works. Not enough lactate for the brain?