I've been doing Nutrisystem for a couple weeks now, and it works! I am losing weight.
Here is the scientific explanation for how it works:
The food is disgusting, so you don't want to eat very much of it,
so you lose weight.
Nutrisystem knows this, and includes the following, helpful exhortation in each packet:
In this the love of God was made manifest among us, that God sent his only Son into the world, so that we might live through him.