They gained weight back when they went off. I think there are some good things and bad things about it, and because of that I think it's a better short term solution than long term, but some good lessons for long term success.
What I liked about it (as someone looking in from the outside) is that it really teaches what an appropriate serving size is. That's something to hold onto even after you've done it for a month.
Where it could use some improvement is that a lot of the foods seem to try to be healthier versions of foods we shouldn't really be eating. (lots of dessert/starchy things)
Because of that, if you decide to go with it, I would consider it a two stage project. One is to relearn portion control if that's an issue for you. And the other is a followup stage where you start working to eliminate sugar addictions. Going back to my mom, she's overweight still but has been losing weight (and regaining some of it). But also she has diabetes now. She is off nutrisystem and is still in the habit of having ice cream every night after dinner - and says she just "needs" something sweet to end the day. If she could have transitioned off nutrisystem to real food and not been in the habit of trying to save calories for dessert, I think her long term success would have been better. All her dessert calories could have been used for protein and veggies, and she could have broken the sugar habit.
I'm saying that not to discourage you from trying this, but to encourage you to think through these issues so you have a better battle plan than she had for how to eat when you get back to regular meals.
Also, if your library has The Four Hour Body, that changed the way I think about food and diets. (Four hours refers to the amount of exercise in a month that the author recommends).
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