Am I the only one who still has flashbacks from the fat-free and low-carb eras? Recently, I was putting together a Running Nutrition Strategy Guide for a client training for a 50K, and as I entered her calorie and macro recommendations, I had a moment. Because even though I know what it takes to fuel a body for endurance training, recommending that many carbs can still feel a little daunting. That’s how deep those old food rules run.

I have a friend named Matt who is an incredible ultra runner. And when I say ultra runner, I mean the long ultra distances — 200 and 250 miles. Over the years, I’ve heard him drop plenty of little nuggets of ultra wisdom, but one has stuck with me more than the rest: “In ultras, the answer is almost always food.”