The Olympics have been incredible this year. I love this story about Michael Phelps' 12,000 Calorie-a-Day Diet. It's so hard to imagine how someone could eat that much every day and stay so healthy! Can you imagine how much ATP gets burned by this swimmer's muscles? The USDA recommends that most average adults consume 2200 calories daily. Most average people would also gain 1 pound each week if they eat 500 extra calories daily. In other words, it takes roughly 3500 extra calories to gain 1 pound.