Approximately, 6.2 million people take part in fitness activities at least twice a month. A great way to help your body shred calories is to speed up your metabolism. Studies show, Protein and mineral-rich foods are key to a speedy and efficient metabolism. Protein-rich foods take longer for the body to digest, temporarily speeding up your metabolic rate by 15-30%. The minerals Iron and selenium can also have a huge effect on metabolic function. Studies show that insufficient amounts of selenium and Iron may reduce your thyroid’s ability to produce enough hormones. Which can slow down your metabolism.