Have you tried Weight Watchers? It teaches you how to eat properly and the correct portions. My biggest problem with some of those 'diet' plans is that once you stop eating their food, you are right back where you started because they don't teach you anything.
I have been doing WW since the end of January and have lost 36 lbs. and I am continuing to lose. I have been on a cruise this summer and only gained 1.2 lbs. because I knew what to eat and how much (I did splurge on the desserts--and that's okay once in awhile!) WW teaches to you incorporate those eating habits into your 'real' life. (Plus, they realize that our generation was raised in the "clean plate club"

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Could I have done it without WW? Probably, but I wouldn't have stuck with it as long or seen as much success. There is something about weighing in each week that makes me accountable, however they also offer their program online so that you don't even have to attend meetings.
If you are going to spend money on a weight loss plan, at least check it out. They have been around forever and they really do work.
Best of luck in whatever you choose!