Diets Make Me Fat

So, I have been on a diet for the last two months.  It's called Weight Watchers.  My mom and sister have been incredibly successful on this diet and have lost weight and kept it off for years.  I tried it before and failed but I decided to try it again anyway.  During my recovery time from my accident I managed to gain 6 pounds.  Not too bad considering I sat on my butt for almost 3 months but still.  I was overweight before I broke my leg and had no room for any extra pounds.  Not to mention that I have a knee to rehabilitate and I know it will get better faster if I weigh less and I'm not asking my body to carry 20 extra pounds.  So, within about 2 weeks on Weight Watchers I had lost those 6 pounds, woohoo!  Then I stalled.  Since then I have fluctuated but pretty much have stayed right at 161.8.  For 2 straight weeks I stayed at 161.8.  I wasn't perfect on Weight Watchers but I was trying and mostly doing it right.  Then, last week I decided to forget WW and started reading about the South Beach Diet.  In the meantime though, I ate sensibly (counted no points though) and tried to make good food choices.  In the last week I have dropped another 7 pounds. I'm hoping to keep those 7 pounds off but not sure if that was a fluke or legit...that's a lot to lose in one week but I'll take it.  I think when I am specifically on a diet I just eat more. On WW I do my best to eat every point I'm allowed for the day and I am thinking about food constantly.  In light of this, I think I'll finish the South Beach book and maybe try some of the principles but just put back into practice all that I know about eating a healthy diet.