How long does it take to lose 7 pounds?

Starving yourself really isn't a sensible option. It'll be uncomfortable, unhealthy and not particularly effective. Going on a real strict diet will cause your body to slow right down, making it even harder to lose weight. On top of that, going on a crash diet makes it real easy to put the pounds right back on when you return to sensible eating habits.

You're better off aiming for a healthier and less strict diet, which together with some exercise will let you lose 1-3 lbs/week.

Cut down on sodas, snacks and everything deep fried, and you can lose those pounds in a healthy manner in 3-4 weeks.