When I ran my first marathon in 2010 (brag), I was surprised by what was shoved in my hand when I stumbled across the finish line. No, not a medal to prove my slow-but-steady 26.2 success—but a serving of chocolate milk. Around me, other marathons were chugging, so I was confused, but also both starving and parched, so I joined in.

“The post-run chocolate milk chug has earned its spot as a tradition because there is science behind it,” says running coach Alysha Flynn. “Chocolate milk has that ideal 3:1 ratio of carbohydrates to protein, which helps replenish glycogen stores and repair muscles after a long run or a hard effort session. It also packs in electrolytes like potassium and sodium to help rehydrate the body, plus calcium and vitamin D to support bone health, which is especially important for women runners.” The best time to imbibe is within an hour of a tough workout.

So in a world where we’re all obsessed with protein, perhaps reaching for the newest high-tech powder and doubling our beef intake post-workout isn’t actually the most effective way to recover—but a little childhood nostalgia is. “Unlike many recovery drinks, chocolate milk is a complete protein with all nine essential amino acids—some of which your body can’t produce on its own,” says Flynn. “It’s not just convenient, it’s surprisingly affordable, and backed by science. And for a lot of runners, it tastes like a treat, which makes it easier to refuel properly.”

But what about just the OG, plain cow’s milk? “Nutritionally, chocolate milk is regular milk with added cocoa and sweeteners,” says Ayla Barmmer, MS, RDN, LDN, and FullWell founder. “The baseline benefits are the same, so you’re still getting protein, calcium, carbohydrates, and some electrolytes like potassium, which are naturally present in the milk. There’s also a small boost from the cocoa itself. Dark chocolate contains flavonoids, a type of antioxidant that may support nitric oxide production. That can help relax blood vessels and improve oxygen flow to the muscles.” Emphasis on small—she says you can actually replicate this nutritional profile with other protein-carbohydrate pairings, though they don’t always include chocolate, so perhaps it’s far less appealing. “Regular milk can work just as well when paired with a carb, like a banana or toast with nut butter. You don’t necessarily need the added sugar from chocolate milk, but the convenience can make it appealing.”