I've tried....
Jenny Craig - learned that it works for a short period of time, but after a while the monotony of food gets to you.
Weight Watchers - learned that I am not very good at counting points/calories
Low fat on my own - learned that doesn't work that well for me
Low carb on my own - learned that I was relying too heavily on processed low carb items
Not eating - learned can lose a lot of weight quickly but hard to maintain
Well i've dieted off and on for at least 20 years (and i'm 29

and basically I've either had a hard time sticking to a diet plan or else that the diet plan wasn't the best for me. I like south beach diet a lot because I feel I am eating healthy and it is something I can stick to.