How many days do you need to be on a low carb diet before you start losing weight?

If you do Atkins and really stick to the induction phase of the diet, you will lose 7-10 pounds in the first 3 weeks. A lot of that is water weight so it slows down after the first few weeks. Then you lose about 1-2 pounds a week until you get close to your goal weight. Then it gets really tough to get the last 10 pounds off.