Michael Phelps is the most decorated Olympian of all time with 28 medals in total, more than anyone else in history. The 37-year-old is widely considered the best swimmer of all time, too. He recently got into golf and is holding his own in that field, too.What people may not know, however, is that the swimmer is a voracious eater. During his swimming days, Phelps was on a wild diet. The recommended daily caloric intake for most people is up to 3,000 calories a day.The Olympian consumed four times that much. Phelps used to eat about 12,000 calories every single day while training. It's one of the most intense diets anyone's ever done.Michael Phelps and food: Exploring why the swimmer ate so much and what he ateMost nutritionalists agree that daily caloric intake shouldn't be too high, though for athletes it is and should be. It's recommended that they consume an average of 1,000 more calories a day.Mashable@mashableThis is what Michael Phelps' diet was like during training 6919This is what Michael Phelps' diet was like during training 😱 https://t.co/ryhQiZSbW6The retired swimmer is well beyond that, though. The biggest reason for this is that his intense training regimen required that much food.The swimmer's metabolism is incredibly high. It's so high that he burns basically anything he eats. During his training, Phelps worked out six days a week for five hours a day.These workouts are so intense that the Olympian has to eat an insane amount of food to have enough energy to train. Most people work out to potentially burn off what they eat, but for the swimmer, it's the other way around.2016 U.S. Olympic Swimming Team Training Camp Media Day (Image courtesy: Getty)He has to eat enough just to be able to burn it off.The Spoon University broke down his daily meals, and they're absolutely insane. For breakfast, this is what he ate:3 fried egg sandwiches with tomatoes, fried onions, mayo, lettuce, and cheeseOne five egg omeletOne bowl of grits3 slices of French toast dusted with powdered sugar3 chocolate chip pancakes2 cups of coffeeIt seems that his intention was to start the day off really well. For lunch, he took it a little easier:A pound of enriched pastaTwo large ham-and-cheese sandwiches with mayo on white bread1,000 calories of energy drinksFor dinner, he had perhaps his lightest meal of the day:Another pound of pastaOne 8-inch pizzaSeveral energy drinksKels@KelsieAnn18The amount of food I’m capable of eating would put Michael Phelps’ diet to shame4The amount of food I’m capable of eating would put Michael Phelps’ diet to shameMost people aren't capable of eating that much food in one sitting, even if it was just the "small" dinner portion. Most people aren't Olympic swimmers, though. And nobody is Michael Phelps.