When my dad was a 12-year-old kid in Red Bluff, California, circa 1928, part of the extended family was a man he knew as Uncle Jack Cotney. That they knew of, or he'd admit to, Uncle Jack had survived some 25 stand-up gunfights in his life.
Green tea is a fat burner that does speed up the metabolism, as far as energy drinks however they really speed up the heart not your metabolism. If you're looking for something that will speed up your metabolism there are better choices for that. Good Luck, Casey.
Fasting and Metabolism. Fasting does not speed up your metabolism -- instead, it has the opposite effect. When your body is deprived of the calories needed for energy, it goes into starvation mode to conserve the energy that it does have. This means you'll burn calories at a slower rate than before.