I did it last year when I got back into boxing. Lost 2 and half stone in 5/6 months. I started introduicing carbs back into my diet in the mornings only (cereal/wholemeal toast) did this for about a month or so and then upped my carb intake more and I have carbs with every meal now as im training pretty intense. I didn't suffer no side effects or fatigue through it and had great results but I suppose everyone is different.