How Michael Phelps Fueled 80,000 Meters a Week (and the 12,000-Calorie Myth)

Michael Phelps, 23 Olympic golds and 28 medals in total, is attached to the most famous nutrition stat in sport: 12,000 calories a day. Phelps has said, repeatedly, that it was never true. The real story is a lesson in how calorie needs work, and why copying a professional's headline intake is one of the easiest mistakes an amateur can make.

The 12,000-calorie myth

The number dates from the run-up to the 2008 Beijing Olympics. Phelps described a day's eating to a reporter, the reporter did the arithmetic and arrived at 12,000 calories, and major outlets repeated it. In his autobiography Phelps wrote, "It's just not true. Maybe eight to ten thousand calories per day." Elsewhere: "I never ate that much. It's all a myth." Even the original 2008 profiles quoted his own figure as eight to ten thousand.

Eight to ten thousand calories a day is still three to four times what a typical adult needs. The myth exaggerated a number that was already staggering.

Why any number that big made sense

At his peak Phelps reportedly swam around 80,000 meters a week, close to 50 miles, in two sessions a day, five to six hours in the water, six or seven days a week. His coach Bob Bowman has said that for roughly five years before the 2004 Olympics, Phelps did not take a single day off: Sundays, Christmas, his own birthday. Swimming is a full-body effort against the drag of water. Hours of it a day, year-round, burns energy at a rate almost no other lifestyle matches.

His intake was the output of his training load. That is why it tells you almost nothing about what you should eat.

Your calorie needs scale with your training

The concept under Phelps's plate is Total Daily Energy Expenditure: resting metabolism plus everything you do, training included. His was extreme because his training was extreme. Estimate what your body uses:

Enter your body stats, activity level and training and you get a realistic daily energy figure. For almost everyone it lands at a fraction of an Olympian's, because almost everyone trains at a fraction of the volume. An hour of endurance exercise for a typical age-grouper burns hundreds of calories, and the hunger after a hard session routinely talks people into replacing far more than they spent. Fuel the training you did. The fast age-grouper post is built on the same reality check.

The most decorated Olympian, then a normal plate

Phelps retired after the 2016 Rio Olympics. The training load ended, and so did the intake. The plate was never about him. It was about the work.

What you can steal from it

• Ignore the headline number. Phelps never ate 12,000 calories, and his real figure only applied to 50 miles of swimming a week.
• Estimate your real needs. Anchor your eating to a daily calorie figure from your body and training.
• Respect how big pro training loads are. The intake made sense only because of ~80,000 meters a week.
• Watch the post-session overshoot. Replace what you spent, not what you crave.
• Fuel the training you did. Your needs rise and fall with your load. Let them.

More in this series: Léon Marchand, coached by Phelps's own coach Bob Bowman, Katie Ledecky and the fast age-grouper on eight hours a week.

Sources

• Wikipedia profile
• NBC Sports
• Two Percent
• The Express Tribune

Cover photo by JD Lasica, CC BY 2.0, via Wikimedia Commons.