I had great results with Atkins and cycling. You just have to remember that when you are cycling, you need more carbs than when you are not. I rode several metric and one full century while watching carbs. Carbs are fuel and you need fuel to go. Don't go overboard and you can still get great results. If you have absolutely no energy, you are restricting your carbs too much. The whole diet is about finding the level that is right for you and it depends on your activity level from day to day. BTW - I lost 40 lbs. 2 years ago and they are still gone.