*With some important caveats
Boston Celtics guard Kyrie Irving—one of the best players on one of the NBA’s best teams—recently made the switch to a vegan diet. So did Portland Trailblazers all-star point guard Damian Lillard and other NBA notables Jahlil Okafor and Al Jefferson. And that’s just in the NBA. Climber Steph Davis, ultrarunners Scott Jurek and Rich Roll, snowboarder Hannah Teter, and former track and field star Carl Lewis have all gone totally plant-powered for at least some period of time during their career.
They’ll tell you that going plant-based has helped them slim down and speed up, as well as provided them with higher energy levels and expedited recovery. If that’s the case, should veganism be your next performance diet? Well, that depends on your goals.
Unless you’re already watching what you eat, veganism will probably help you lose weight, says Trevor Kashey, an Ohio-based biochemist and sports nutritionist who regularly works with professional athletes. Lillard, for example, says that prior to going vegan, he ate whatever he wanted, a method that put him at a slightly heavier weight than he wanted. He made the switch to “play lighter” and be “easier on [his] joints and feet,” according to an interview with the Oregonian. Now, after nearly five months on a plant-based diet, Lillard’s choice has him feeling the positive impact, with the dominating stats to prove it.
“It shouldn’t be shocking that when you switch from eating lemon pepper wings to tofu and kale, you lose weight,” says Kashey. Research suggests that most omnivores eat a greater number of calories per day—up to 600 more, in fact—than vegans, who gravitate toward filling, low-calorie foods like vegetables and grains and avoid calorie-dense, animal-based foods.
Such weight loss may indeed be easier on your joints and give way to new, higher limits for your athletic ability. “Basketball is a game of sprinting, cutting, and jumping, and any excess weight on your body, even if it’s muscle, increases the cost of the impact you make with the ground,” says Doug Kechijian, a physical therapist who has consulted for various NBA teams. “If you lose weight but keep your strength and quickness, the physical cost of playing the game becomes less expensive.” This same rule applies to any sport that involves frequent moderate- to high-impact contact with the ground, like running or skiing.
Many staples of the American diet—cakes, burgers, pizza, wings, fries—“might make you feel a bit sluggish” if eaten regularly, says Kashey. So it’s not totally surprising that once they cut those things out, Irving and others see leaner body composition and more energy, both of which lead to noticeably better performance. Perhaps, then, it’s more about which foods these athletes are now avoiding rather than what they’re adding that makes the most difference.
That’s what Bill Willis, a nutrition researcher at Ohio State University, believes. He thinks cutting out overprocessed animal products might be the game changer, not necessarily eliminating things like meat, cheese, and eggs altogether.
In short: The vegan diet is not the only way to see significant improvement. If your primary goal is to lose weight, most research suggests you can do that eating anything you want, so long as you eat fewer calories than you’re burning. But top-tier athletes aren’t just looking for a weight-loss strategy. They also want something that keeps them fuller for longer, ups their energy levels, improves recovery, and, overall, takes their abilities to the next level. Well-sourced animal products with little to no processing can still play a key role in achieving those goals.
That’s especially true for strength and power athletes, because building muscle on a vegan diet can be tough. Without very careful planning, vegans generally eat less protein than their omnivore counterparts, and the plant proteins they do eat aren’t as bioavailable as animal proteins, meaning the body can’t put them to use as easily, says Willis. A few other hurdles: One study reports that vegans face deficiencies in essential micronutrients like vitamins B12 and D, calcium, and omega-3s.
Bottom line: While you’re likely to see performance benefits from a switch to veganism, especially those that relate to being a few pounds lighter, it’s not a panacea to being faster, stronger, leaner, and better than you’ve ever been before. That aside, going the plant-based route is a smart choice for general health. Vegans tend to live longer and seem to have a lower risk of chronic diseases like diabetes, cancer, and heart disease. “I don’t think you can rule out that people are increasing their health from a plant-only diet,” says Willis. Just be sure to approach the diet intelligently. “You can’t just replace animal products with a bunch of sloppy carbs,” says Willis. Oreos, Pop-Tarts, Lay’s Barbecue Chips, and Burger King french fries, for example, are all vegan.