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Endurance Sports Nutrition: Frequently Asked Questions

Consuming variety of carbohydrates during exercise and eating balanced training and recovery diet improve performance

What should athletes participating in endurance and ultra-endurance exercise eat before, during and after sports? Here the answers to these and other questions about endurance sports nutrition:


Q.  What should an endurance sports athlete eat during a long run, bike ride or other exercise that lasts more than 60 to 90 minutes?

A.   It depends. Some athletes like the convenience of engineered sports foods. Others prefer the taste (and price) of standard supermarket foods, such as fig bars, dried pineapple, and gummy candy.  The bottom line: all are equally effective.

And because we're talking more about "survival" rather than  "good nutrition" during endurance exercise, you don't have to feel guilty if you use candy as fuel. Sugar (e.g. simple carbohydrates) is what your body wants!  Remember, too, that sports gels and sports drinks are also "just sugar."

  Does it matter if you get your energy from an energy bar or a sports drink?

A.  The short answer is no. Both solid and liquid energy foods get burned at the same rate when exercising for more than half an hour. So, again, what an athlete eats depends on what his intestinal tract tolerates and what tastes best.

Consuming enough calories is more important than the form of the calories because research suggests that endurance athletes who consume more calories do better than athletes who consume fewer calories. (For example, Ironman Triathlon champ, Chrissie Wellington, consumed about 335 calories/hour when she won in Hawaii.) 

The challenge is to train the intestinal tract to digest that much fuel and convert it to energy for the body to use. In other words, the training program for an endurance athlete actually needs to include training of the intestinal tract as well as the heart, lungs and muscles.

Q.  How much should an athlete eat to maintain good energy during exercise lasting longer than 60 to 90 minutes?

A.  The rule of thumb for fueling during endurance exercise used to be to consume 1 gram of carbohydrate per minute of exercise (e.g. 60 grams of carb per hour or the equivalent of 240 calories).  The research, originally done with just glucose, suggested that consuming more than 60 grams of glucose per hour offered no extra benefits because the body has a limited number of glucose transporters and can carry only 60 grams out of the intestines into the blood and to the muscles.

Recent research, however, shows that consuming a variety of sugars (e.g., more than just glucose) makes more fuel available to the muscles per hour. That's because different types of sugars (carbs) use different transporters.

Most endurance athletes are already consuming more than just glucose:  Sports drinks, for example, contain glucose and fructose. while a banana is made up of many different types of sugars and uses many different transporters. An athlete's muscles will be able to access more fuel (up to 90 g carb/hour or 360 calories per hour) if he consumes more than just one kind of sugar. 

The new research has resulted in new recommendations on the optimal number of grams of carbohydrates to consume during endurance exercise:

Fueling During Exercise

Exercise Duration
Grams of Carbohydrates Per Hour
Less than 45 minutes

No fueling during exercise required

(other than pre-exercise snack)

1 to 2 hours
30 g. carbohydrates (120 calories) per hour 
2 to 3 hours
60 g. to 80 g. carbohydrates (240 to 320 calories) per hour1
More than 2.5 hours

90 g. mixed carbohydrates (360 calories) per hour (sports drink,

candy, dried fruit, pretzel)

Some serious athletes train first thing in the morning without eating before/during exercise. While doing this may teach the body to burn more fat (hence spare limited glycogen stores), it's grueling and the verdict is unclear if it enhances competitive performance. Stay tuned!

Q.  What happens if fueling during exercise creates intestinal distress?

A.  Consider a  "swish and spit" approach.  Research shows that athletes who just swished and then spat out a sports drink performed better than athletes swishing and spitting just plain water. How could that be? It's because receptors in the mouth are linked to the brain so that when an athlete's mouth gets a swish of sports drink, it sends a signal to the brain - which then sends a signal to the body -  that energy is on the way, so it's okay  to work harder.


Protein requirements are hard to define because the amount of protein your body needs depends on how many calories you consume. That is, if you are restricting calories, you require more protein than when you eat adequate calories because the protein gets burned for fuel. Dieting athletes should target at least 1 g protein/lb (2 g pro/kg).

Note: If an athlete is dieting to reduce body fat, it is hard to build muscle mass at the same time because building muscle takes energy, while dieting restricts energy.

The protein recommendations for non-dieters who consume adequate calories are:

  • Healthy adults: 0.4 g Protein/pound 0.8 gm Protein/kg
  • Strength athletes: 0.5 to 0.8 g Protein/pound 1.2 to 1.7 g Protein/kg
  • Endurance athletes: 0.5 to 0.6 g Protein/pound 1.2 to 1.4 g Protein/kg.

Q.  Does an athlete need to take protein supplements (such as by consuming protein shakes)?

A.  No.  Because the typical athlete's diet contains more than enough protein, most athletes do not need protein supplements. A protein-rich food with each meal and snack will do the job.

Q.  During endurance exercise, should you choose a sports drink with protein?

A.   Not unless you prefer the taste; it does not offer performance advantages over a standard sports drink. The better time to consume protein is after exercise because consuming carbs plus protein (such as in a specially formulated recovery sports drink containing protein and carbohydrates, or chocolate milk, fruit yogurt, or spaghetti & meatballs) helps the body recover from exercise by enhancing muscle repair and by replenishing glycogen stores in muscles, which are a source of fuel during prolonged exercise.2

Balancing carbs plus protein

Consuming some carbs+protein before a workout, as a part of a pre-exercise meal (cereal+milk, fruit+yogurt) is another option to bolster the supply of protein available both during and after exercise for recovery.

Note: Athletes generally don't burn much protein for fuel during exercise unless their glycogen (carb) stores are depleted. The bottom line: Meals/snacks with carbs as the foundation, protein on the side offer the right balance for endurance performance.

Updated  August 30, 2011

© Nancy Clark (article)

© MomsTeam.com (video)

Nancy Clark, MS RD CSSD, is MomsTeam's sports nutrition expert, a Certified Specialist in Sports Dietetics and best-selling author.  She counsels active people in her practice at Healthworks, a fitness center in Chestnut Hill, Massachusetts. Her new book, Food Guide for Soccer: Tips & Recipes from the Pros and other books, including her Sports Nutrition Guidebook and food guides for new runners, marathoners, and cyclists are available at www.nancyclarkrd.com and www.sportsnutritionworkshop.com.


Jeukendrup, A. Sports Nutrition: From Lab to Kitchen. Meyer 7 Meyer Sport, 2010

Mettler S, N Mitchell, K. Tipton. Increased protein intake reduces lean body mass loss during weight loss in athletes. Med Sci Sports Exerc. 42(2):326-337, 2010.

Rollo I. M. Cole, R. Miller and C. Williams. Influence of mouth rinsing a carbohydrate solution on 1-h running performance. Med Sci Sports Exercise 42(4):798-804, 2010.

Jeukendrup, Asker, Rodriquez, Nancy, presentation at 27th Annual SCAN (Sports Nutrition Group of American Dietetic Association), April 2010. 

1. According to research presented at the annual meeting of the American College of Sprst Medicine in Baltimore, Maryland, June 1-5, 2010, cyclists and triathletes who consumed 60 to 80 grams carbohydrate per hour (240-320 calories/h) performed better than those who consumed 10-50 or 90-120 grams of carbohydrate per hour.  By experimenting with different amounts of carbs during training, you can learn the right amount for your body.

2. Research studies presented at American College of Sports Medicine's 57th Annual Meeting, June 3, 2010.

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