Well, I've never joined a program, but I thought I'd share my mother's experience with you.

She had really bad cholesterol levels, and the doctor told her she had to cut out everything with more than 4% fat in it. She had to do that for three months, and she lost 15kgs. It's easy to tell what the % of fat in a food is, just look at the amount of fat per 100gms, and if it's more than 4gms, it's a no go.

But when I lost all the weight before my wedding, I didn't change any eating habits, and barely changed my exercise habits too. I just willed it off. Just power of the mind over the body I guess.