Welcome back, friends! Season two of the Endurance Eats podcast is here, and we’re diving straight into a hot topic that’s buzzing all over social media—ketones. You’ve probably seen the flashy ads featuring elite athletes endorsing ketone supplements, and like me, you might be wondering: Are they really worth it?

To help us get to the bottom of it, I sat down with Dr. Jonathan Little, a professor in the School of Health and Exercise Sciences at the University of British Columbia. With over 200 peer-reviewed publications under his belt, John brings a deep scientific perspective to the conversation—plus, he’s a former endurance athlete himself. Together, we unpacked what ketone supplements actually are, what the science says about their effectiveness, and whether they have a place in your fueling and recovery strategy.

What Are Ketone Supplements Anyway?

Ketones are naturally produced by your liver during periods of fasting, starvation, or when following a ketogenic diet. But with the advent of exogenous ketones, you can now drink your way into a mild state of ketosis without having to fast or cut carbs.

There are three main types on the market:

1. Ketone Monoesters – Most potent, most studied, and most expensive.
2. Ketone Salts – Less effective, and they can wreak havoc on your gut due to high sodium content.
3. Ketone Precursors – These require conversion in the liver before they become usable.

Most of the research—and any potential benefits—are focused specifically on ketone monoesters. So if you’re seeing wild claims online, make sure to check what type of ketone supplement is actually being promoted.

Ketones & Performance: Hype vs. Reality

The initial excitement came from a 2016 study suggesting ketones could improve endurance by sparing glycogen. But since then, over 20 follow-up studies have struggled to replicate those results. In short, the consensus is: ketones won’t give you a noticeable performance boost.

In fact, in high-intensity efforts—think 5Ks, 10Ks, or threshold workouts—ketones might even impair performance. And for athletes already on a ketogenic diet, supplementing with ketones may actually suppress your body’s natural ketone production due to an increase in insulin. Yikes.

Recovery & Cognitive Benefits: Some Hope on the Horizon?

Now here’s where things get a little more interesting. While ketones may not boost your PRs, there’s emerging (but early) research suggesting they might:

• Support muscle preservation post-exercise.
• Improves sleep quality when taken before bed.
• Enhance erythropoietin (EPO) production, possibly mimicking some benefits of altitude training.
• Aid cognitive performance late in long events (though caffeine probably does a better job).

Still, these findings are in their infancy and mostly based on small studies. So if you’re on a tight budget or averse to bad-tasting drinks, it might be best to wait for more conclusive research.

GI Distress & Real-World Practicality

Let’s be real: the taste of ketone monoesters is awful. And while they’re not as likely to cause major GI distress as ketone salts, they could still interfere with your post-workout appetite. Some pro athletes pair them with sodium bicarbonate to offset acidity, but unless you’ve dialed this in perfectly (and tolerated it well under race-day stress), the risk likely outweighs the reward.

Final Thoughts: Should You Use Ketones?

If you’re a recreational endurance athlete or even a competitive age-grouper, the science just doesn’t support using ketones to improve performance—yet. However, there might be niche scenarios (like supporting sleep or cognition in extreme events) where they offer a small edge. But for now, I’d save your money and focus on nailing the basics: carbs, hydration, protein, and sleep.

Massive thanks again to Dr. Jonathan Little for cutting through the noise and sharing science-backed insights. Whether you’re intrigued, skeptical, or somewhere in between, I hope this helped you make an informed decision about ketones in your training and racing strategy.

If you found this post helpful, please share it with a fellow endurance enthusiast, and don’t forget to check out the full podcast episode for even more depth and nuance!