runners hydrating prior to long run

Nutrition plays a critical role in performance during exercise or competition. When you under-fuel or eat the incorrect foods, you put yourself at a huge disadvantage to perform at your highest level. This is especially true for endurance athletes who depend on sustained fuel over long distances. Overall, a diet for endurance athletes doesn’t change all that much when it comes to what is healthy. Runners still want to focus on lean protein, fruits, veggies, and whole grains. The main difference is the timing of these foods and how much to fuel your workload. For context, when I mention “long-distance”, I’m referring to events lasting multiple hours like a long run, marathon, or ultra-marathon. 

Pre-workout fuel is extremely important and could make or break your upcoming run. Aim to consume 1 gram of carbohydrate per kilogram of body weight two hours before and consume 20 ounces of water two hours before the start of endurance training1. Carbohydrate loading is only necessary if performing in a long-distance race like a marathon or longer. This means you don’t have to eat multiple bowls of pasta the night before a 5k! When needing to carbo-load, just aim to increase your carbohydrates in each meal for 3-5 days before your race. This could look like going from 1 cup of cooked rice to 1.5 cup cooked rice. A great pre-workout snack could be one or two slices of toast with peanut butter, Greek yogurt with granola and fruit, or oatmeal with peanut butter. The biggest thing to worry about is eating too much fat and fiber before a run, including the night before. Loading up on a healthy salad the night before a race can lead to a slow-digesting meal that causes gastrointestinal issues on race day. 

NHW Runner

During your run, consume food only if you are running for 90 minutes or longer. For runs 90 minutes or longer, consume a carbohydrate gel that has roughly 25g of carbs every 20-30 minutes. The gel I recommend to my clients is Maurten gel. Consume water or an electrolyte beverage throughout the run, even if you are not thirsty. Dehydration will always win, and once you lose 2% of your body weight, you will struggle to perform. Hyponatremia is also another concern on long runs or races. Hyponatremia is when your sodium blood levels drop, which can cause a decrease in performance, fainting, and even death at its most severe. This is another reason why having salt in your diet can be crucial for a long-distance runner. Salt is unfortunately viewed as unhealthy by many but that is farthest from the truth. So don’t skimp on the saltshaker!

Post-training fuel is often missed because people usually do not have an appetite after a hard training session. Blood can be prioritized to working muscles instead of the stomach, which reduces appetite. Regardless, it still becomes vital to get in a good balance of carbohydrate and protein within an hour of exercise. Try to consume 1.5 grams of carbohydrate per kg body weight within the first 30 minutes post-exercise, 15 to 25 grams of protein within the first 30 minutes post-exercise and 24 ounces of water for every pound of body weight lost1. To figure out how much water to consume, weigh yourself before and after a run to see how many pounds of sweat you lost. One pound of sweat is 16oz of water you need to replace along with around 500mg of sodium that is also lost. A great post workout snack or meal could be a turkey and cheese sandwich on white bread, protein smoothie with fruit, or a protein bar with a banana. 

Your daily calorie goal depends on your training load. Most new runners make the mistake of overconsuming food because they think they are burning an enormous number of calories. At the end of the day, going for a 3-mile run will net you around 300-400 calories burned. This can add up if the miles keep increasing, but it’s easy to consume 300-400 calories quickly. So, make sure you fill up on nutrient-dense foods throughout the day to prevent weight gain. Try out our metabolic machine to better understand how many calories to eat per day depending on your exercise!

When you look to adjust your nutrition strategy for exercise, you must try it in training first. Do not make the mistake of trying a new food or supplement on race day because that can bring unwarranted risk for gastrointestinal distress. What works for your friend might be completely different for you. Talk with one of our registered dietitians to understand which strategy is best for you.




  1. Nutrition for endurance. ISSA. Accessed December 12, 2021.