It is just a typical diet for losing weight quickly, i.e. a diet that provides only around 800 kcal/day, while providing normal quantities of proteins, essential fatty substances, vitamins and minerals, to avoid other health problems.
I assume that you get a box in the mail with your food, marked for specific meals, and you can only eat what's in the box and nothing else. There is no deviation (unless you cheat) but no complaining about the cost of food or difficulty of preparation.
Also I expect the number of people who could follow this diet to be extremely low, but I also don't know how it would compare to the average dieting plan.
You need to restrict calorie intake significantly for 3 month period for metabolism to change for the desired result. Many people could not finish the program.
Weight helps to treat symptoms and has huge health benefits even without remission.