By now, you’ve probably heard about the ketogenic diet—you know, the one that allows you to eat *all* the healthy fats (and almost totally nixes carbs). Traditionally used to treat patients with epilepsy and other serious health issues, the keto diet has made its way into the mainstream and is especially popular with the fitness crowd. While it’s true that it may have some performance benefits, experts say there’s some very important info you need to know if you’re planning to exercise while on the keto diet.
You might not feel so great at first
And, naturally, that might affect your workouts. “You may feel like you are in a fog for the first few days,” says Ramsey Bergeron, C.P.T., a seven-time Ironman, keto athlete. “Your brain’s primary fuel source is glucose (from carbs), so as it switches over to ketone bodies created by breaking down fats in the liver, it will take some adjusting.” Luckily, the mental fog will typically pass after a few days, but Bergeron recommends skipping workouts that require quick reactions to stay safe, like riding your bike on roads with cars or doing a long, challenging outdoor hike.