So, you want to take your training and performance to the next level but aren't sure where you fall on the nutrition side of things…
The debate on the necessity of carbs has been going on for decades, and there is still no end in sight.
However, more recent research suggests that despite popular opinion and the rise of low-carb and keto for performance, carbs still very much have their place in an athlete's diet.
And especially for endurance athletes who need that pool of reserves, and they need it now.
But because all carbs aren't created equal, we're going to help you navigate through all the misinformation and confusion out there and give you our top picks for the best carbs for endurance athletes.
Types Of Carbohydrates: Slowly Absorbed vs. Rapidly Absorbed
Fueling an endurance athlete through a gruesome race requires a substantial amount of fuel, and while fat provides an almost unlimited substrate supply, the conversion rate isn't fast enough to supply immediate energy to working muscles.
The liver can store approximately 80-100g of glycogen, whereas skeletal muscle has a much larger capacity of around 400-500g.
However, it's important to note that the brain primarily pulls from liver storage, but the rest of the body relies on muscle glycogen stores.
But in terms of what types of carbs you want to fill or replenish those stores, here's what you need to know.
Research suggests that glucose's absorption rate into the bloodstream can influence exercise intensity and duration 1.
They suggest that rapidly absorbing carbs higher on the glycemic index are better at providing working muscles with the energy needed to sustain exercise and maintain performance.
Some sports nutritionists suggest that consuming slower-digesting low-glycemic carbohydrates pre-workout promotes a blunted rise in the blood glucose response, which may be preferential pre-exercise.
This provides a more sustained release of glucose into the blood, and thus a more sustained supply of energy. However, there is little research to actually support this for endurance performance.
Some research even shows that there is little difference between pre-event consumption of low GI carbs or high GI carbs on the ability to maintain or improve high-intensity running performance 2, so as long as you're consuming carbs, you're likely good to go.
However, the post-workout window requires carbohydrates that are quickly digested, absorbed, and transported in the blood to alter the hormonal milieu and enhance glycogen resynthesis, which is a key factor in recovery from strenuous exercise.
Experts suggest approximately 0.5-0.6 g/kg of rapidly absorbed carbohydrate every 30 minutes for 2-4 hours after endurance exercise to sustain a high rate of glycogen synthesis for athletes' training on consecutive days 3.
Why Carbohydrates Are Essential for Athletes
It's no question that athletic performance can be altered based on the availability of specific substrates to provide immediate fuel for training.
There is ample research available indicating that muscle glycogen is a critical substrate for training at intensities of 70-80% VO2max, and endurance performance can be either enhanced or reduced by changing levels of muscle glycogen.
A study conducted by Christensen and Hansen in 1939 was one of the foundational studies pointing to the importance of carbs for athletic performance 4.
They examined the difference in energy contribution during endurance activity based on varying dietary intake of carbohydrates. One diet consisted of 83% CHO and 3% fat, whereas the other comprised 94% and 4% CHO.
They found that the contribution of carbohydrates to total energy expenditure was substantially higher in the high-CHO diet, but the exercise duration was also more than double that of the high-fat group; 210 minutes versus 88 minutes.
Bergstrom et al. also confirmed these results, suggesting that a high-carb diet could enhance submaximal exercise performance.
Working at a capacity of 75% VO2max, the higher the initial glycogen stores, the longer the performance could be sustained 5.
However, in recent years the idea of high-carb for performance has been challenged by the rise of the ketogenic diet.
The underlying idea behind keto and performance is the almost unlimited supply of fatty acids during exercise that negates muscle glycogen depletion and eliminates the need for carbohydrate supplementation during exercise.
But despite some evidence suggesting the benefits of keto for ultra‐endurance‐athletes, there isn't a large amount of evidence linking LCHF to endurance performance in elite athletes 6.
In light of all the available research, most studies still support the notion that carbs are required to maximize performance, be it endurance or strength.
The Best Carb Options For Endurance Athletes
With all of that said, it's time to get to the best options for carbohydrates. There are one of two ways you can go about carbs: food or supplements.
Food is always the best option for pre-and post-workout nutrition; however, with the rise of high-quality carb supplements, there are also some good options available that supply a sustained-release source of energy.
Fruit offers both a great source of quick-digesting carbs besides loads of important micronutrients to support optimal body functions.
Bananas are a staple for most athletes because they offer a fair amount of carbs (24-27g) with just 3 grams of fiber.
The fiber content is enough that it will slow down the sugar absorption subtly, but not enough that it will sustain glucose release for hours.
The carbs are ingested as both fructose and starch and will either enter muscle cells or maintain blood sugar levels, depending on levels of stored glucose.
Basically, bananas are a perfect balance: the fast-acting carb count gives immediate energy, while the fiber makes it more sustainable for the entire workout duration. Bananas are also loaded with potassium, vitamin B6, and even small amounts of vitamin C.
Potassium is an important electrolyte required for maintaining proper fluid balance and is often depleted during intense exercise.
But potassium is also needed to maintain proper cardiovascular and respiratory functions, along with sodium, blood volume, and muscle contractions 7.
Dried fruits also offer a concentrated source of fructose to supply an immediate boost in energy. However, be mindful of the quantity you're consuming, as sugar levels are much higher in dried than fresh fruit, and you don't want to go overboard.
White rice, chicken, and broccoli have been a staple meal for bodybuilders for ages. Because of the perfect ratio of protein to carbs, it offers the best post-workout meal.
Cup for cup, white rice is among the highest carbohydrate (starch) count of any grain.
With minimal fiber, it's quickly broken down and absorbed to spike blood sugar levels and shuttle amino acids directly into the muscles to start the repair process.
Pre-workout, it does a similar job. The starch is put towards increasing blood sugar for immediate use or pushed into glycogen storage.
But why white rice over brown?
Athletes and lifters recognize the value of high glycemic foods like white rice to provide quick fuel for intense and prolonged workouts, as well as facilitate muscle recovery.
Unlike brown rice, white rice doesn't have any potential gastrointestinal (GI) issues, allergy symptoms, or block the absorption of key micronutrients.
Along with other grains, Brown rice contains phytic acid—an anti-nutrient that binds to essential minerals like iron, zinc, calcium, and magnesium and prevents their absorption.
Phytic acid is located in the grain's bran, so the milling process to turn brown into white rice removes the phytates.
Beans and Legumes
For athletes following a vegan diet, beans and legumes are a must. Not only do they provide a good dose of protein and fiber, but they're also a great source of carbs to supply sustained energy for endurance athletes.
Despite being a low GI food, studies suggest that a low GI pre-game meal may prolong endurance during strenuous exercise by lessening postprandial hyperglycemia and hyperinsulinemia, lowering levels of plasma lactate pre- and intra-exercise, and by maintaining plasma glucose and free fatty acid concentration at higher levels during critical periods of exercise 8.
Keep in mind that proper preparation methods are key to prevent GI issues with beans and legumes.
Like we said about brown rice and anti-nutrients, the same applies to beans and legumes.
Soaking them overnight before cooking helps reduce anti-nutrient content and improve digestibility, thus preventing gas and bloating that often accompanies consumption of beans and legumes.
There you have it. If you're looking for sustained endurance performance, including carbs in your diet is key, but finding the right one can be challenging.
We've given you our top 3 recommendations for clean carb sources that will provide you with sustained energy during your workout and accelerate your recovery post-workout.
If you're unsure where to start, try one and see how it affects your workout and recovery. And don't be afraid to try them all before figuring out which works best for you.
- M Kanter. High-Quality Carbohydrates and Physical Performance: Expert Panel Report. Nutr Today. 2018;53(1):35-39.
- JP Little, PD Chilibeck, D Ciona, et al. Effect of low- and high-glycemic-index meals on metabolism and performance during high-intensity, intermittent exercise. Int J Sport Nutr Exerc Metab. 2010;20(6):447-456.
- DT Thomas, KA Erdman, LM Burke. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance [published correction appears in Med Sci Sports Exerc. 2017 Jan;49(1):222]. Med Sci Sports Exerc. 2016;48(3):543-568.
- EH Christensen, O Hansen. Arbeitsfähigkeit und Ernärung. Skandinavishes Archiv für Physiolgie. 1939; 81: 160–171.
- J Bergström, L Hermansen, E Hultman, B Saltin. Diet, muscle glycogen and physical performance. Acta Physiol Scand. 1967;71(2):140-150.
- JW Helge. A high carbohydrate diet remains the evidence based choice for elite athletes to optimise performance. J Physiol. 2017;595(9):2775.
- MI Lindinger, G Sjøgaard. Potassium regulation during exercise and recovery. Sports Med. 1991;11(6):382-401.
- DE Thomas, JR Brotherhood, JC Brand. Carbohydrate feeding before exercise: effect of glycemic index. Int J Sports Med. 1991;12(2):180-186.