Michael Phelps-- stands 6 feet 4 inches and some say he has a size 14 foot, but what makes Phelps uniques is his Olympic diet. After getting his record breaking 11th Olympic Gold Medal ... US swimmer Michael Phelps, at the 2008 Olympics just recently revealed the secret to his incredible body and Gold Medal outcomes. The formula he would have you know behind his physique is a surprising 12,000-calorie per day diet.