So how many calories would you burn in a day just to keep your basic systems functioning? The average male burns about 1800 and the average female about 1200. Endurance athletes have bigger engines that burn even more at rest. It wouldn't be unusual for those numbers to be 50-75% higher. I had mine tested two years ago and it was just under 3500 calories. Throw in some of the typical activities of the day like work and working out and I have many days above 5000 and even in the 7-10,000 range. Building muscle is the key to building metabolic rate. Muscle burns about three times the calories at that fat burns. Build your big muscle groups to burn the most calories. Our digestive system accounts for about 10% of our metabolic rate so eating burns more calories. Be sure to spread your meals out for the best efficiency. After a hard workout of 45-60 minutes our metabolic rate will spike for up to an additional 14 hours. Another reason to keep high intensity workouts on your schedule and to see someone like Dawn Weatherwax at Sports Nutrition 2Go. She can test your metabolic rate, sodium loss, and body fat %.