Running nutrition may seem complicated, but it doesn’t have to be.

In recent years, the conversation around optimal race day fueling strategies for runners has intensified, focusing particularly on the ideal carbohydrate intake per hour to enhance performance and endurance. Should you consume 50 grams per hour? 100 grams? 1000 grams?! (okay, don’t try that last one…)

Today, Coach Sandi Nypaver will take you through the latest science on exactly how you should be fueling for your next race. This evidence-based approach aims to maximize glycogen stores, sustain energy levels, and prevent the dreaded “bonk” or energy crash that can derail even the best-prepared athletes. As you seek to fine-tune your running nutrition strategy, understanding the science behind nutritional requirements becomes essential for achieving peak performance on race day.

Here we go:

You could have just had the best training cycle of your entire life, but if you don’t execute on the things I’m about to talk about, you could underperform; or worse, you could have a total disaster of a race. But I’m here to help, and we’re going to start with one of the things that I see runners get wrong all the time…


One important piece of nutrition that is often overlooked is hydration, and research has repeatedly shown that dehydration significantly impairs performance. One primary reason is that blood volume decreases, leading to an elevated heart rate as the body compensates. Additionally, electrolytes, especially sodium, are crucial for maintaining fluid balance and supporting metabolic activities, such as muscle function.

In other words, when we’re dehydrated, our muscles fatigue faster and muscle contractions weaken. Many people confuse bonking with dehydration. While bonking can often come on suddenly and feels like hitting a wall, dehydration tends to develop more gradually. It manifests as a progressive increase in fatigue, with heavy legs and an overall sense of tiredness. Recognizing these symptoms in past races or during current training can help identify the onset of dehydration.

Sodium Needs (to combat dehydration) 

For fluids, aim for 12-24oz per hour, or more in hot conditions, keeping in mind that your body can only absorb so much at a time and over-drinking can cause serious problems. For sodium, most people need between 300-600mg per hour on average, though some may need less and others closer to 1000+mg per hour. Keep in mind that the fueling plan you use on cool days at low altitude may not work during hot conditions or at higher altitudes. When possible, test your plan in potential race conditions and have backup options, such as switching to a sports drink that provides both electrolytes and calories.

When I started applying this to my own training, the biggest change I noticed was that I felt stronger at the end of the run. My energy levels were better not only during the run but also afterward. I see this with many people, especially in the summer when they often finish a run feeling exhausted and wiped out for hours. Even though running can naturally tire you out, a significant part of that fatigue is due to dehydration. It’s crucial to pay attention to fluid consumption and how much water you mix with electrolytes.

Race Day Carb Needs 

When looking at the latest research (and still recognizing that fueling can be highly individual), here are some general guidelines:

  • For a race lasting 1-2.5 hours, aim to consume around 30-60g of carbs per hour.
  • For races over 2.5 hours, increase your intake to around 60-90g of carbs per hour. Some runners may even be able to consume up to 120g per hour.
    • However, even 60-90g per hour requires practice during most long runs to ensure your gut can handle it during a race. It’s important to stay flexible and adjust your intake if your stomach starts to feel unsettled.

To reiterate, it’s important to recognize that not everyone has the same needs. Some products might work for you, whereas others may not. For instance, people with fructose malabsorption cannot tolerate high amounts of fructose, as it can upset their stomachs. Experiment with different products and find what works for you. If you rely on aid stations, research what they offer and practice using those products during your long runs.

For more detailed coaching on pacing, nutrition, and mindset, consider exploring our Ultimate Running Course, “Coach Yourself to Your Highest Potential.” More on that below.

To Recap…

Optimal race day fueling and hydration are individualized and require careful experimentation and planning. Understanding your body’s needs, practicing with different products, and adjusting based on conditions and personal tolerance can significantly enhance performance and comfort during a race. By integrating these strategies into your training routine and being mindful of your nutrition and hydration, you can set yourself up for success and achieve your highest potential on race day.

Happy running!

  • Coach Sandi