Most of us would end up being seriously obese if we ate 10,000 calories per day, but not Michael Phelps. In an interview with ESPN he said his calorie consumption per day ranges around the 8,000-10,000 mark, including large quantities of pasta and pizza. Apparently, he is partial to fried egg sandwiches. Some dietitians have written in to Medical News Today telling us that 10,000 calories per day is most unlikely for a 6 foot 4 inch Olympic swimmer.