Dr. Nick Tiller is an exercise scientist at the Lundquist Institute at Harbor-UCLA, a two-decade ultrarunner, and the author of The Skeptic's Guide to Sports Science and the new The Health and Wellness Lie.

In this conversation: why ultrarunning is, by Nick's cheerful admission, not actually good for you, and why we keep signing up anyway; the red flags that should trip your bullshit detector in 2026; the great protein panic and how a "health halo" turns a Pop-Tart into a recovery food; what the evidence does and very much doesn't say about AG1; KT tape, cupping, and the slippery ethics of selling someone a placebo; and how to stay skeptical without curdling into a cynic whose brain has fallen out.

This episode is brought to you by LMNT, the new Lemonade Iced Tea flavor has been quietly fixing our hydration and our 4pm coffee regrets; grab a free sample pack with any order at drinklmnt.com/UltraSignup.

Featured race: the Ode to Laz Michigan Backyard Ultra, a 4.167-mile loop run every hour on the hour through 8,000 acres of Holly State Recreation Area in Holly, Michigan, on Saturday, July 18. The only way to win is to be the last runner standing, which is why the motto is "finishing last means the most." If you're backyard-curious but not ready to sign over your soul, the Oak Flats 3-hour option lets you dip in for one, two, or three loops. It's a championship-affiliated race, so the winner takes a silver ticket toward the USA national backyard team. Registration closes Thursday, July 16. Sign up at UltraSignup.com.

The Trailhead is part of the UltraSignup Podcast Network.