I've heard a lot about this and many people find it works.
I think the main thing is everyone on this diet tends to eat less which helps with weight loss as that is purely an energy equation.
I do think the intermediate part may help with stabilizing digestion and glucose levels which would lead to a longer life expectancy amd less diseases above and beyond what weight loss in general will achieve.
Overall a good combination.
It does lend itself to further speculation - and it's not like it can hurt you (like taking medication) - so I'm giving it a try.