I have only been on Atkins for 2 weeks 5 days but I have already lost 14lbs...I would say that is a pretty rapid weight...esp. for someone who couldn't lose 1lb on fat free or low calorie...Well my thyroid is under control as far as I know(I am due for a doctor vist and blood work) and I am 150mcg synthroid and I am losing...I sure hope I don't have to increase up to that amount..well at least not soon I like not having an appetite...Its great eat to live not live to eat..I love it...