Bonk generally refers to when you haven't been refueling properly for your ride.

For me it feels like I'm riding in mud and it comes on suddenly.

Lately I've been having trouble with bonking even when I'm not riding. I've really upped my output in the last few months, but apparently the input is sometimes not sufficient to keep up.

To avoid it, I drink water mxed with Sustained Energy at least every 15 minutes and I eat something solid every 30 minutes. I usually don't start eating until I've been out for an hour though. And if I'm doing a short ride (for me sub 2 hours) I use Gatorade instead of Sustain.

Good luck!

V.