The sight of a pro athlete chugging a sugary soda after a close game was bizarre enough to light up social media. 

When Green Bay Packers quarterback Aaron Rodgers drank grape-flavored Crush during a postgame news conference in November, some figured there could only be one explanation. His choice of beverage had to be a dig at the purple-clad Minnesota Vikings, whom the Packers had just beaten.

Mr. Rodgers dismissed the idea as “ridiculous.” His explanation was surprising. He said he’s been drinking grape or orange soda after every game for seven years.

In an era when many athletes have become obsessed with nutrition, Mr. Rodgers’s soda routine reveals a surprising truth: Many high-level athletes not only drink the occasional soda, they use it strategically to fuel their performance. This persists amid the vilification of sugary soft drinks as a contributor to the nation’s high rate of obesity.

French tennis pro Gaël Monfils amused spectators in September when he drank from a can of Coke during a fourth-round victory over No. 7 seed Grigor Dimitrov.

The Ironman triathlon series serves flat cola and Red Bull to competitors in its grueling swim-bike-run events. Elite marathoner Camille Herron says she drinks three to four cans of Coke a week to help provide calories for her 100-mile training regimen.

Ted King, a member of the Cannondale Pro Cycling team, estimates that 90% of the riders on the Tour de France drink Coke at some point during the race.

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