I tried the Nutrisystem diet about eight years ago, combining it with a couple hours of walking each day, and I lost more than forty pounds in one month. I ended up with severe gallbladder attacks. It turns out that men, in particular, are prone to gallbladder problems when they lose too much weight too quickly. I then lost whatever my gallbladder weighed because that was removed. I mentioned that in their forums, not as a complaint, but simply as a report, and a bit of a warning, and I was attacked by other forum members. A couple of days later, the thread was removed. I am sure there have been some changes over the years but, with Nutrisystem, you buy most of your food from them, choosing from their breakfasts, lunches, dinners and snacks. The idea is that any breakfast, any lunch, any dinner, and any snack from Nutrisystem would make up a good diet. There are a few things that need to be purchased fresh from the grocery, but most everything is supplied by Nutrisystem. It is a very easy diet to do, and it is very effective as long as you don't cheat. Other than their chocolate snacks, none of their foods were excellent, the best being on the level of a top-line TV dinner. Some of their foods are good, some are not so good, and others are awful, but the idea was that once you found out what tasted awful to you, you wouldn't have to order that anymore. After a few months though, I was losing only a pound or so a month, so it was harder to stay on the diet, and easier to become persuaded that it was too expensive to spend that kind of money on a couple of points a month. What finally did it for me was their snacks. At least half of their snacks were on the awful side, while most of the others were not exactly delightful, but I did like their chocolates. However, after ordering the chocolates as nearly every snack choice one month, they sent me only a couple of them, with a notation that they were on back order. The same thing happened the next month, and the snacks there were replacing them with were from the awful category, and since they still listed the chocolates as a snack choice, I got the idea that they were simply refusing to let me choose them. So I quit.
I had a niece who was on the Nutrisystem diet. She lost a lot of weight on it. She said that it wasn't that expensive when you consider that it made up all your food expenses. Sadly, she eventually gained all the weight back. I think it all comes back to eat sensibly and exercise.
Most all fad diets fail because they don't address the problem that caused the overweight which is a mineral deficiency. Theory that eating less and exercising more has failed just look around if it was that simple everyone would be thin. It is not genetic if it was where did the gene come from 100 years ago everyone was thin. Of course you could put a person in jail and only feed him very little and he would become thin [Auschwitz] but if people have food available and they are hungry because the body tell them so they will eat.
I have never been comfortable with the idea of receiving food that is prepared in advance in boxes. The dry food that just needs to have water added has never sounded healthy to me.
I've looked at their diet and also Jenny Craig's but never tried them. I've tried weight watchers but that didn't work for me at all. Seems that I did the best on South Beach and the 17 day diet. Low carb works for me. Atkins is too low carb but I did do it once.