While I’m generally a proponent of eating a low carbohydrate (for weight-loss) or moderate carbohydrate diet (for sustainable health), a number of studies indicate that ultra endurance athletes, athletes who compete in events longer than 90 minutes in duration, perform better when they have an adequate supply of glycogen.  Glycogen is the body’s stored form of glucose, and is one of the primary sources of energy for endurance activities where the average percentage of vo2 max is greater than 65%. Glycogen stores, which are found in the muscles and connected to the liver, are best replenished by consuming an ample amount of carbohydrates.

While studies have found that ultra-endurance athletes on a low-carbohydrate diet can adapt to better utilizing fat for energy, it turns out that these athletes are not able to perform as well as a athletes with adequate stores of glycogen.  Numerous studies indicate that endurance athletes on high-fat diets experience greater levels of perceived exhaustion and usually aren’t able to perform as well as athletes on high carbohydrate diets.

While in rats and some people, it’s been found that extremely high fat diets (greater than 75%of the diet), do promote high levels of endurance in combination with training, the greater body of evidence supports high-carbohydrate intake for increased ultra-endurance performance.  Should growing evidence change this indication, we’ll let you know! Otherwise, follow the carbohydrate-loading recommendations below to optimize your ultra-endurance performance.  

Amount of Carbohydrates for Optimal Training and Competition
The optimal amount of carbohydrate consumption for ultra-endurance exercise it thought to be between 2.5 and 4.5 grams of carbohydrate per pound of bodyweight.  Of course, this is a big range.  This means if you weigh 150 lbs and regularly run more than 90 minutes per day, you’ll need 375 – 675 grams of carbohydrates per day.  You can start to narrow down this range by topping out your carbohydrate intake at 600 grams per day.  At least one study indicates that carbohydrate levels above 600 grams may not provide additional benefit.  Further narrow down this range by calculating your basic macronutrient and energy needs to determine how many additional calories you need from carbohydrates.  For example if your basal metabolic rate (the calories you burn just living) is 2500 calories and you burn an additional 3,500 calories running a 50k, then you should eat the full 600 grams of carbohydrates, which equals 2,400 calories.  However, if you only burn 1,475 calories running a half marathon, then you’ll only need to consume the minimum of 375 grams of carbohydrates (375 X 4 cal = 1,500 calories).

Ratio of Macronutrients
The best ratio of macronutrients (fat, protein, carbohydrates) for ultra-endurance athletes is a topic of debate, but I think the current evidence suggests that a balanced ratio, high in proteins, is optimal for muscle regeneration and energy production.  

Here’s what I recommend:

  • Start with the amount of protein your body will need to repair itself from the tremendous catabolic effects of endurance exercise — approximately 1 to 1.4 grams of protein per pound of body weight. For example, if you weigh 150 lbs, you’ll need a minimum of 150 grams of protein per day (600 calories from protein).
  • Aim to meet approximately 40% of your body’s basal metabolic need for calories by an intake of healthy fats (butter, avocados, coconut oil, meat, eggs).  For example if your basal metabolic rate is 2,000 calories, aim to get 800 calories from fat (89 grams of fat).  Fat is vital for a healthy nervous system and for repairing cells.
  • From there, fill the rest of your caloric need in with carbohydrates based on your amount of training/competition.  For example, once you’ve obtained 1,400 of your calories from protein and fat, you’ll still need 600 calories from carbohydrates (150 grams of carbohydrates) just to meet your minimum calorie need, assuming it’s 2,000 calories.  So, if you burn an additional 3,000 calories per week running, then you’ll need to include an additional 750 grams of carbohydrate in your diet, which can be spread out evenly throughout the week.  To optimize glycogen storage, you can also concentrate the consumption of these 750 grams of carbohydrates in a few days, which will help you achieve the recommended 2.5-4.5 grams of carbohydrates per pound of bodyweight.

Macronutrient Overview

  • Protein – 1-1.4 grams of protein per pound of bodyweight
  • Fat – 30-40% of total basal metabolic calorie need (daily calorie need without exercise)
  • Carbohydrates – 2.5-4.5 grams of carbohydrate per pound of bodyweight, depending on energy expended in ultra-endurance training.
  • A side-note: For the most part, high quality fats and carbohydrates are interchangeable for energy needs, feel free to vary the ratios of carbs and fat based on your individual calorie needs and how you are feeling during exercise.  Keep in mind that eating the most balanced ratio of protein:fat:carbs possible will promote improved digestion, nutrient absorption, and stable blood-sugar levels.

Quality of Carbohydrates
While carbohydrates are frowned-upon in paleo and low-carb fitness circles, the evidence indicates that its not the amount of carbohydrates that negatively impacts health, as mush as the quality of carbohydrates.  Get as many of your carbohydrates as possible from whole-food, nutrient-rich sources, such as greens, sweet-potatoes, beets, carrots, quinoa, and raw, unfiltered honey.

Avoid processed sugar, such as that found in candy, sugar, ice cream, and other refined foods.  These types of sugars negatively affect the body’s health in numerous ways. Read our previous article on Why Sugar is Toxic for more information.

Carbohydrate Loading
The original method of “carbohydrate-loading” involved a seven day process of limiting carbohydrates for 3-4 days during intense training, followed by 3 days of rest and carbohydrate gorging. While effective at increasing glycogen stores, this method proved taxing and disrupted athletes’ ability to engage in optimum training levels before an event. 

The most recommended form of carbohydrate loading is merely an extension of normal carbohydrate fueling.  Instead of drastic depletion and repletion, ultra-endurance athletes should increase the amount of their carbohydrate intake towards the upper level of 600 grams per day,  starting 3-7 days before a competitive event, while simultaneous tapering down their amount of training.  

Best Times for Carbohydrate Consumption
For optimal energy supply and glycogen repletion, healthy carbohydrates should be consumed immediately before and immediately after training or competition.  

  • From 2 hours to 30 minutes before an event, endurance athletes may experiment with consuming .5 to 1 gram of carbohydrates per pound of bodyweight.  The more carbohydrates one plans to eat, the earlier the carbohydrates should be consumed.
  • Endurance athletes should also aim to consume about .5 grams of healthy carbohydrates within 30 minutes after an event. 

Amount of Carbohydrates During the Event
Endurance athletes can digest and utilize approximately 1 gram of carbohydrate per minute of activity. Thus, during ultra-endurance events, athletes should be consuming about 60 grams of carbohydrates per hour.  Just remember, everyone is little different in terms of what they are able to digest, so the actual amount will take a little bit of personal experimentation.  You may be able to utilize anywhere between 45 and 75 grams of carbohydrates per hour.  

A Note on Weight-Loss Versus Athletic Performance
Keep in mind that these recommendation are for ultra-endurance activities of 90 minutes in duration or longer.  Also, such high-levels of carbohydrate intake are primarily for improving athletic performance, not for weight-loss.  If weight-loss is your goal, it may be better to stick with a low-carbohydate/high-protein diet and mix your endurance training with high-intensity exercises, such as sprinting and weight-lifting.  

Sources: “High Carbohydrate Versus High Fat Diets in Endurance Sports,” by Asker E. Jeukendrup; “Endurance and Ultra-Endurance Athletes,” Jones and Bartlett Publishers

Originally posted 2013-09-03 17:35:05.

Tags

No responses yet

Leave a Reply