Years ago (before taking up running) I did the Atkins diet - all protein, no carbs and despite its many critics I found it really did work. Not only did I lose weight, I gained energy. The key to both that and the article above in my opinion is the ability to avoid or massively reduce your sugar intake! The item about sugarfree drinks is interesting - sugar drives more consumption of itself through its effect on your insulin levels etc. Its a sneaky little substance!