There are a lot of different diets, but none of them is new, there are not much new inventions the last few years.
In many diets the most important effect is that you are aware of what you eat al day. This is already effective by itself.
There is also evidence that proteins are more satiating than other macronutrients, this means that if you eat more proteins, you will eat less.

After only a few days diabetes could be gone. That is dependent on absorption and that changes a lot after surgery. The absorption is going down and it could be that you have to take vitamine supplements for the rest of your life.

Also people can fall back really hard. There are people addicted to food adn they cannot stop eating.

Surgery is one of the only things that really helps for obesity, but it is not easy.

- Decrease food consumption
- Reduce energy absorption from GI tract
- Reduce body fat by stimulatin genergy expenditure or inhibiting energy
- Reduce inflammatory status
- Modulate body fat distribution, energy fluxes or minick physical exercise
- minimize pathophysiological complications.