Jillian Michaels, my biggest girl-crush, says that moderate amounts of caffeine, when coupled with exercise, boost testosterone levels. Testosterone helps you increase your energy, shed fat and build more calorie-burning muscles. She recommends 200 to 400 milligrams of caffeine a day, which is about 2-4 cups of coffee. Yippee Skippee! Something I love that is actually good for me! I am grateful for my morning coffee.