I've gone no carbs a couple times with really good results. Usually it is something the wife and I do after the holidays to get back to our desired weights. Doing it with a disciplined exercise regimen led to 10 pound loss in two weeks last time. It is not a life style I can do for much longer than about 3 weeks though. If the goal is to drop some weight quick I think it works but of course if you fall back into poor eating habits the weight will come back. I never had any issue with stamina/weakness only that I felt hungry a lot more.