Watermelon’s stock has shot up in recent years, likely thanks to Beyoncé. Pink cocktails aside, people are touting the delicious juice as a smart choice pre- or post-workout thanks to its replenishing electrolytes and muscle-boosting amino acids. Some even go as far as saying that it’s the perfect recovery drink. We looked into it: Should you drink watermelon juice after a workout?
This trendlet assumes that you need a special, rehydrating beverage after a breaking a sweat. While sports drinks have a purpose, a lot of people don’t need them, says Caroline Kaufman, MS, RDN. They’re marketed to the regular exerciser, but they’re really intended for use after workouts that are longer than an hour, take place in hot weather, or leave you with salty sweat trails. In those cases, you need to replace fluids as well as electrolytes lost through sweat, namely sodium and potassium. After shorter, less intense sessions, regular old calorie-free water will do the trick, Kaufman says. “Sports drinks, soda, and energy drinks are one of the top sources of added sugar in our diet, and that seems to be more of a problem than people walking around dehydrated,” she adds.
Say you soldiered through a 60-minute bootcamp class. Is watermelon worth it then? Though the fruit does naturally contain potassium, the bottled juices have zero sodium, so they don’t have enough electrolytes to be a good sports drink, Kaufman says. (For the record, the big coconut-water brands contain a small amount of sodium, but it’s still much less than what you’d find in, say, Gatorade.)
As for the amino acids, researchers think that a compound in the flesh and rind of watermelon called citrulline might improve blood flow and help reduce muscle soreness or even improve athletic performance. But the studies thus far have been on small groups of recreational athletes (given either watermelon juice or L-citrulline supplements) and any benefits found weren’t that impressive, according to Kaufman. In a 2013 study, cyclists who drank watermelon juice were slightly less sore 24 hours after exercise than people who drank a placebo, but at 48 hours post-workout, everyone rated their soreness the same.
That’s why Kaufman thinks watermelon “water,” cold-pressed juices, and citrulline supplements are gimmicky — though she’s open to changing her mind if and when more research comes out. In the meantime, she wouldn’t tell most people not to drink watermelon juice (or any juice, for that matter). “If you like watermelon juice and it helps you drink more water, drink it,” she says. Just know that it has 60 or more calories per serving, depending on the brand, so factor that in to what you’re eating the rest of the day.
One caveat when it comes to juices in general: Liquids don’t help you feel full. If you’re having weight-control or blood-sugar problems, whole foods or smoothies are likely better options since they have more fiber. “If you wake up and have a green juice and feel great, awesome,” Kaufman says. “But if you’re seeing some effects, like you’re really hungry, you’re hangry, I would go back to food.” For the same amount of calories in a 15.2-ounce watermelon juice sold at Trader Joe’s, you could have three cups of diced watermelon and a glass of water. It would take you longer to eat, occupy more space in your stomach, and make you less likely to be hungry five minutes later.