Nutrition in Action

One of the most common topics of concern from athletes doing long distance events is nutrition. Athletes constantly come to me asking questions about what to eat, what to drink, and how much to eat and drink. Let’s start to answer some of those questions.

The most important part of a complete training and racing nutrition plan is actually the hydration. Water. A lot of people skip over that and go straight to the latest and greatest bars, gels, gummies, or whatever else is out there. Water! Water by itself, or water in a sports drink. It has been shown that your central nervous system actually fatigues before your muscles fatigue. That means that your brain sending a message to your legs telling them to run breaks down before the muscles in your legs are actually tired. Proper hydration allows the signals in your CNS to continue to function. For more on hydration, check out this article on sweat rates to figure out how much you need to be drinking.

The second piece of a complete nutrition plan for training and racing is calories. Calories provide the energy that your body burns for fuel during exercise. During an endurance event, your body primarily relies on fat for fuel. This fat is already stored on your body – and yes, even the leanest endurance athletes have fat to burn. In order to access those fat stores, your body first needs to have some carbohydrates (stored in your muscles as glycogen) to burn. What that means for you is that you need to eat a little bit of food during exercise that is entirely made of carbohydrates and that will allow your body to burn its fat stores for the rest of the energy it needs. If you’re getting into ultra-distances, you can also add a little protein to that (5-10%).

For more on the differences between fats and carbs as well as protein – the third macronutrient – check out this article.

How many calories to eat

The number of calories to shoot for is dependent on your body weight. Smaller athletes need to consume fewer calories and bigger athletes need to consume more. Also, ultra-distance athletes can try increasing their consumption. Follow these guidelines.

Most race distances:

1.3 x Body weight in lbs. = calories per hr.


1.8 x Body weight in lbs. = calories per hr.

Once you get these numbers for your weight, compare that to the number of calories you’re burning per hour during exercise. Most people can find that pretty easily by using any of the many workout trackers that are out there. Make sure that the number you’re targeting to eat is less than half of the total number of calories that you’re burning. If you’re on the slower side, you may be able to cut back on the number of calories these equations predict.

What to eat

What to eat is an extremely personal question. I say that because what your stomach can tolerate is different than what my stomach can tolerate and is different than what your friend’s stomach can tolerate. As long as you follow the guidelines above in terms of carbohydrates and the number of calories, the rest is up to you when it comes to what to eat. In fact, Sarah often jokes with me that she’s going to try eating Nerds on her long runs. I don’t think she’s actually tried it yet, but at a basic level Nerds are really not that different than some of the sports drinks out there. You can probably pick something a little better than Nerds, but you get the idea.

Also keep in mind that I say this as an athlete and coach with no affiliation to any sports products. I don’t have any sponsors whose products I’ve agreed to promote and I don’t sell any products myself. There are a lot of sale reps out there that will tell you their product is the best for you and have a lot of reasons why. Try their samples, try some other samples, and figure out what works for you. The key is to find something your stomach tolerates and also tastes good to you.

Modifying the Plan for the Conditions

Fast forward to race day. You’ve been training and practicing with the nutrition plan and things are going great. Now you find yourself on race day and it’s 20 degrees hotter than what you’re used to, what do you do? This is the most common scenario that I see with endurance and ultra-endurance athletes. Especially for those of you doing Ironman, it’s going to be hot by the time you start that run. What do you do?

The most important thing is to drink more water (and more sodium in proportion). In extreme heat, you’re going to be sweating more and you need to stay hydrated.

You do NOT need to eat more calories. There is a limit to the rate that your body can metabolize calories. Do not eat more calories than what we already planned on. In fact, if it’s so hot that you find yourself slowing down and slowing down significantly to the point where you’re walking on the run, you can cut back on the number of calories you’re eating. At that slower pace, you’re burning fewer calories so you can cut back on your intake as well.

The final thing that I want to say about a nutrition plan is that all of this data and all these calculations gives us a starting point. It’s important that you find this starting point and then start experimenting with it during your longer workouts. What works, what doesn’t work? What changes can you make? Listen to your body and watch for the signals that it’s sending you and you’ll be ready for race day!

Summer is Coming!

As the weather warms up, we can finally stop worrying about freezing in the cold and shift our focus to getting in longer workouts outside in the sunshine. For anyone training for a race that lasts longer than about an hour and a half, it is extremely important to stay hydrated. Not only that, but the longer the race, the more important hydration becomes – marathon, half Ironman, and Ironman people I’m talking to you! There’s more to staying hydrated than just drinking water. You need to consider your sweat rate and sodium intake in addition to the water that you drink. Here’s a breakdown of how it all works.


Your sweat rate is simply how much you sweat during your workouts. If you know how much you’re sweating (water out), you can figure out how much water you need to drink (water in) to stay hydrated. It varies depending on how hot it is, how hard you’re working, the sport you’re doing, and the weather conditions (sunny/cloudy, hot/cool, calm/windy). Not only does it vary depending on external variables, but it also varies by internal variables – you! Sweat rates vary tremendously from one athlete to another. In fact, if you compared sweat rates to shoe sizes, it’d be like shoe stores having to carry size 2 to 200 to accommodate everyone! Because of this, I highly recommend doing a sweat rate test. If you can do multiple tests in varying conditions, it’s even better.

A sweat rate test will tell you how much you sweat. With this info, you can figure out how much you need to drink so that your performance doesn’t suffer from dehydration. All you have to do is weigh yourself before and after a workout to see how much weight you lose. Make sure you weigh yourself right before you start and right after you finish. It also works best to take off any sweaty, wet clothes. 16 oz. of water weighs 1 lb. So, if you weigh 153 lbs. at the start of a 40 min run and 152 at the end, that means that you lost 1 lb or 16 oz of water and that your sweat rate is 24 oz of water per hour running. Repeat the test in different conditions and for different types of workouts to get an idea of how much your sweat rate varies and so that you can better predict what your sweat rate will be on race day.

Drink Water

Now that you know how much you’re sweating, you need to replenish most of that with water. Water from sports drinks like Gatorade, Infinit, or Skratch counts too. You don’t actually need to replenish all of it though. You can lose around 2-3% of your body weight to dehydration before it starts to impact your performance (some studies show even more). That means you can compare your sweat rate to how much you’re drinking and aim to be 2-3% lighter at the end of the race and you’ll be great. That also means that you might have different hydration plans for races of different durations.

Role of Electrolytes

The last thing to consider is the role that electrolytes – particularly sodium – play in hydration. Proper sodium levels allow your body to absorb the water that you drink. Too much or too little can cause issues. There are two ways to determine the right amount of sodium for you. The first is to get a test done that measures the sodium concentration in your sweat. You can get great info from an official test, but it will cost around $100 depending on where you go. The second way is to estimate it based on your own observations like whether you crave salty foods when you finish a workout or notice your skin covered in salt crystals after working out. Put yourself on the range of high, medium, or low saltiness and pick 500-1500 mg of sodium per hour accordingly. This is what you should shoot for in terms of sodium intake. You can get sodium from your sports drinks, salt pills, or solids like granola bars during your workouts and races.

Put it All Together

Now you should know how much to drink and how much sodium to consume to make sure you absorb the water appropriately. Keep in mind that since your sweat rate varies based on the conditions, you may need to adjust things on the fly. For example, if it’s really hot on race day, you’ll want to drink more water than usual. Not only that but you’ll want to increase your sodium intake proportionally along with it.

Keep this all in mind and take the time to do a sweat rate test. It truly is priceless information to have and can make the difference between a great race and a terrible race. I speak from experience. There was one 50k that I ran where I was fighting serious stomach pain the last 8 miles of the race. I finished and literally lay in the fetal position in the finish area for over an hour. Finally, I ate some potato chips that they had in the finish area for the runners and immediately started to feel better. I ate 3 more bags and was back to normal within minutes. My sodium intake was off, I wasn’t absorbing the water I was drinking, and it was causing serious gut rot. If I had had that dialed in better during the race, I probably could have finished 20-30 minutes faster.