Green Tea

How: Boosts metabolism through antioxidants, fat burning stimulant through caffeine content.
Ginger

How: Enhances thermic effect of foods. Ginger promotes energy expenditure, feelings of appetite and satiety and metabolic risk factors in overweight men.
Proteins

How: Increases metabolism by requiring your body to use more energy to digest them.
Iron, Zinc, Selenium

How: All three are required for the proper function of your thyroid gland, which regulates your metabolism. Research shows that a diet too low in iron, zinc or selenium may reduce the ability of your thyroid gland to produce sufficient amounts of hormones. This can slow down your metabolism.
Caffeine

How: Caffeine stimulates the nervous system, which sends direct signals to the fat cells, telling them to break down fat.