I was on 20 grams of carbs/day for 7 months. Lost weight... but mostly inches. I do exercise. Cardio every day, weights every other. I felt pretty good on it, some aches and pains went away.
It was hard to do at times, I missed fruits and veggies.
I quit when I started losing my hair. It's supposed to be a somewhat common / temporary effect. I'm not that vain, but I felt my body was trying to tell me something.