How Caffeine Works Biologically

Find full episode transcripts, show notes, and research at yourdietsuckspodcast.com. Grab merch at teepublic.com/user/your-diet-sucks. And if you want bonus episodes, early access, and our eternal gratitude, support us on Patreon at patreon.com/YourDietSucks.

Caffeine is the most widely consumed psychoactive substance on earth — and somehow it's still got two extremely loud camps screaming past each other. On one side: the wellness-bro "caffeine destroys your adrenals, drink my mushroom latte" crowd. On the other: the guy on TikTok who takes 800 milligrams a day and wants you to up your dose. Both of them are wrong. Both of them are extremely entertaining.

In this episode, Zoë and Kylee dig into how caffeine actually works, the adenosine receptor science, the performance research, the optimal dosing for endurance athletes, and what it's actually doing to your sleep, hormones, and anxiety levels (spoiler: more than you think, less than the fear-mongers claim). They trace the history of human caffeine consumption from ancient China to Sufi monks using coffee as a pre-workout for night prayer, through the Enlightenment coffee houses that accidentally invented capitalism, all the way to a 300-milligram neon energy drink with a skull on it.

There's also a full breakdown of the pre-workout industry's stimulant escalation problem, why adrenal fatigue isn't a real diagnosis, how your menstrual cycle affects caffeine metabolism, and whether the caffeine taper before a race is actually worth the two weeks of misery.

Plus: the 1904 Olympic Marathon featured rat poison, brandy, and a man who hitched a ride in a car for 11 miles. Dry scooping sent multiple people to the hospital. And "energy is a choice" is not a peer-reviewed finding.

We cover it all.

This episode is supported by rabbit — use code YOURDIETSUCKS10 at runinrabbit.com/collections/womens-new for a discount on their trail line. By Osmia Skincare — use code YDS20 at osmiaskincare.com for 20% off. By Tailwind Nutrition at tailwindnutrition.com. And by Microcosm Coaching at microcosm-coaching.com.