I have been following the South Beach diet for about a month or so. I'm trying to follow phase II right now which includes good carbs. For the most part, I have felt good.

Today I had planned a 30 mile ride. I woke up kinda dragging, felt like it took alot of energy to walk the dog around the block. I ate breakfast- eggs and toast & milk- about an hour before I left, still kinda dragging and I thought, maybe just go out for 10 miles, see how it feels. I rode about 4 miles, couple of small hills and I started feeling very weak, dizzy, sweating, I ate a few bites of granola, which was hard to do and I slowly went back home hoping I didn't pass out on my bike. When I got home, I drank some gatorade and ate some crackers and laid down, after awhile I felt better. I checked my blood sugar after this and it was 105. So it was probably quite lower.

I had gestational diabetes with my kids, I don't have diabetes now, but I tend to be glucose intolerant. My numbers run a little high.

Yesterday I didn't eat many carbs, but I thought I would be ok with eating breakfast before I went out.

Was this a bonk? Do I need to eat more carbs the day before I ride?