3. Eat more protein
While eating food in general increases your metabolism for a few hours, protein causes the biggest increase. This is because food requires extra calories to digest, absorb, and process the meal, which is called the thermic effect of food (TEF). Protein can increase your metabolism as much as 15 to 30 percent, and can also cause you to eat less. So if you increase the amount of protein in your diet, you should be well on your way to a higher metabolism.