Protein fuels the muscles, boosts metabolism and keeps hunger at bay. Breakfast is the most important meal of the day. It revs up your metabolism, builds up your energy for the day and makes you just feel good. The key? Eat a high-protein and low carb balanced breakfast. And don't forget your morning booster, coffee. More studies revealed in 2015 alone showed the caffeine, chlorogenic acid and antioxidants in coffee help fight chronic diseases like cancer and diabetes. 3-4 cups of black coffee per day are optimal.