I find cellulite is different for everybody. My cellulite completely goes away when I do not drink alcohol and eat very clean - wholegrains, healthy lean proteins, limit the salt intake, limit the coffee and uncultured dairy, no sugar, lots of fruits and vegetables and I always drink lots of water. When I juice fast it does not disappear for me although my skin generally is very clear elsewhere.
If I have one night on the alcohol and eat the hangover crap the next day my cellulite comes back shortly after.
As for stretch marks, I don't worry about them but if you do there is an expensive cream out there called Strivectin. It completely fades stretch marks. It is also well known for anti aging. A friend used it with great results for getting rid of wrinkles.