Well, according to Cosmopolitan, a green apple once a day, flaky white fish and chicken are all good foods to boost the metabolism. Don't know how true it is but that's what Cosmo says.
I've heard of green apples and ginger. I always add ginger to my food and tea, and even some of my desserts. I prefer red apples to green ones, but apparently they are of no use in weight-loss because they are too starchy.