Does Alcohol Play Into Carb Loading for Endurance Athletes?

Dayna Player Robinson
7 days ago
3 min read

Updated: 12 minutes ago

Carb Loading &

Alcohol for Endurance Athletes

As race day approaches, endurance athletes start thinking seriously about carb loading, hydration, and gear.

But if you’ve ever signed up for an ultra, Ragnar, or trail race, you’ve probably noticed something else on the menu: beer.

From beers at the finish line to whiskey at mile 50 aid stations (we’re looking at you, trail ultras), alcohol has woven its way into endurance culture. But how does alcohol affect carb loading—and ultimately—your performance?

Let’s break down the science, the myths, and what athletes should really consider when it comes to that pre- or post-race drink.

(Inspired by a text from one of my run coach athletes.)

Alcohol and Calories: How Does It Stack Up?

When talking about carb loading, calories matter—but so does where they come from.

Carbohydrates: 4 kcal per gram
Protein: 4 kcal per gram
Fat: 9 kcal per gram
Alcohol: 7 kcal per gram

Yes, alcohol is calorie-dense. But unlike carbs, fat, or protein, it’s what we call non-nutritive. That means it provides energy—but no vitamins, minerals, or fuel that the body can actually store as glycogen.

When you’re carb loading, the goal is to increase the muscle’s glycogen stores so you have extra fuel for race day. Alcohol not only doesn’t help with that—it can interfere with it.

What the Research Says

Several studies highlight alcohol's negative effects on endurance performance, particularly in the final 24–72 hours before a race:

A 2010 review in the Journal of the International Society of Sports Nutrition noted that alcohol impairs glycogen resynthesis, especially when consumed post-exercise (Parr et al., 2010).
A study published in Sports Medicine (Barnes, 2014) found alcohol delays muscle recovery and reduces muscle protein synthesis following strenuous training sessions.
A 2020 piece in Precision Hydration reported that even small amounts of alcohol can increase dehydration, impair temperature regulation, and reduce sleep quality—all crucial for performance and recovery.

Alcohol and Race Culture: Let’s Be Real

Let’s not ignore the culture: beer miles, finish line brews, champagne sprays at podiums. In trail and ultra running, especially, alcohol is often part of the experience.

But just because it’s there doesn’t mean it’s helping.

Having alcohol in your system the night before or the morning of a race can impair coordination, judgment, and hydration status. Drinking right after a race—before rehydrating or eating—slows down the recovery process when your body needs nutrients and fluids most.

This doesn’t mean you can’t enjoy a drink. But as with most things in endurance sports, timing and intention matter.

Best Practices for Athletes Who Enjoy a Drink

If you’re an endurance athlete who enjoys alcohol, here’s how to do it in a way that supports—not sabotages—your training and racing:

Avoid alcohol during carb loading (especially 48 hours before the race): You want every gram of glucose to go toward glycogen, not processing toxins.
Hydrate before you celebrate: Post-race alcohol can delay rehydration and exacerbate muscle soreness. Always prioritize water, electrolytes, and food first.
Watch your sleep: Even one drink can disrupt REM sleep, which is crucial for physical repair and mental clarity.
Moderation is key: If you do choose to drink, stick to 1–2 servings post-race, after your recovery routine is underway.

Final Thoughts: Cheers or Jeers?

In the big picture, alcohol doesn’t contribute to carb loading and may impair performance and recovery when consumed too close to race day. That doesn’t mean you need to swear it off completely—just be smart about when and how you indulge.

When athletes ask me, “Can I have a beer after the race?”—my answer is: sure, after you’ve hydrated, eaten, and cooled down. A cold beer is better enjoyed with a strong finish and happy legs.

Happy running

Dayna - your fav. Exercise Physiologist

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