I intend on trying the water fast (drinking only water) for high metabolism. will i be able to keep the 9-10 pounds off by doing this?

Nope.: The weight you lose is going to be temporary. Whatever diet you choose - paleo, adkins, water, beach, grapefruit, mediterranean, etc. - the weight will not stay off. Stick with the usual life-long concepts of portion control, regular exercise, and decreasing salt & sugar intake. Any diet program you choose needs to be one that can last you a lifetime.

Boomerang: This will have a boomerang effect. Your metabolic rate will drop.