I've been going Primal for about 2.5 weeks now, only "cheating" for one meal or so each weekend. Sunday was my first road ride since starting (65 miles, ~ 16/mph avg speed). I'm 28, male, 6'0" tall, 180 lbs. Earlier this summer I was riding 60-95 miles without too many issues, but I've been off the bike for much of the past month.

My breakfast Sunday was a Primal smoothie (10% milkfat Greek yogurt, berries, 1 tbsp of honey), a few slices of bacon, and 2 eggs with cheese. A few hrs later I had about 2 tsbp of almond butter before hopping on the bike.

I felt a bit slow and thirsty 20 miles in so I had a 32 oz Gatorade, which seemed to give me some energy. Around mile 40 I had a 2 more tbsp of almond butter, and noticed I was a bit tired. I stayed hydrated with plenty of water.

I started feeling really tired around mile 55, and nauseous around mile 62. At mile 64 or so, I realized I couldn't make it up the small 100-ft hill and 3 extra miles back home without vomiting or collapsing, and stopped in a parking lot and called my girlfriend to pick me up. It was an outright BONK like nothing I've experienced before in a years of riding, hiking, and running. I was having problems thinking clearly, had no appetite, and almost no energy. I didn't really feel 100% again until today, almost 48 hours later.

How do you cyclists deal with this? Should I just "cheat" and eat a few carbs (I used to eat granola bars every 25 miles or so, and lots of Gatorade) on the bike? Will my body eventually adapt to riding Primal? I also noticed I had a lot less energy climbing hills than I used to. Previously, I'd eat a big dinner the night before, than a bagel with lots of Nutella for breakfast right before a big ride. I like the weight loss Primal is giving me (I was overweight before due to carbs, despite going on 60-95 mile rides often), but would also like my cycling energy back. I have a charity ride in a week and a half with 100 mile rides Saturday and Sunday that I'd like to finish without bonking. "Cheating" will probably work for that ride, but my goal is to be able to ride Primal without cheating or bonking....