Monday, June 27, 2011

Protein for the Endurance Athlete...How much is enough?

By Anne Guzman 
Peaks Coaching Group Nutritionist
Pro Cyclist


Peaks Coaching Group Anne Guzman Nutrition

As endurance athletes our bodies require different amounts of nutrients than our more sedentary counterparts. Long term research indicates repeatedly that endurance athlete should consume a diet of approximately 60% carbohydrates, 20-25% fats and 15-20% protein.[i] One area that seems to be misunderstood is the proper requirement for protein for endurance athletes.
Proteins are made up of amino acids. 20 different amino acids are commonly found in proteins. Humans can synthesize 11. The other 9 must be received through the diet. These are referred to as Essential Amino Acids. The body needs all 20 amino acids. The following will help you understand how much protein you need as an endurance athlete.

Whereas the average non athlete may eat a bit more protein to help them stay feeling more full or simply because it the way they prefer to organize their diet, as endurance athletes we don’t really have that luxury. It is important that we have enough carbohydrates to fuel our exercise, which means that we would have more carbohydrates than the everyday person in place of their higher protein calories. Although in the following pages you will see that protein is important for bodily functions, there is a limit to how much we require and can use for fuel.

The majority of endurance athletes consume TOO MUCH protein in their diets. With the billion dollar diet industry pushing Low Carbohydrate and Zone-esque like diets, some athletes also seem to have jumped onto the high protein, lower carbohydrate bandwagon. Whether it be in an attempt to lose weight or simply because athletes believe this is what they need to perform optimally, it is a mistake. Although we do need protein, it is not the endurance athlete’s fuel of choice. These diets are for weight loss and are calorie and carbohydrate restrictive. A recipe for BONKING!

As an overweight person the scenario is different and a diet with a bit more protein can help with weight loss and feelings of fullness. But again, we are talking about the athlete. And the athlete needs to PERFORM.

The bottom line for endurance athletes is that carbohydrates and fats are the necessary fuels for energy. Our diets need to have 60% carbohydrates for FUEL and recovery as well as to SPARE PROTEIN. In the sports nutrition community carbohydrates are often said to have a “protein sparing effect.” What this refers to is that we should eat  at LEAST 60% carbohydrates (or follow the proper grams per kilogram according to your training level)  in order to spare the protein for its routine uses in the body. Protein is required to make antibodies for the immune system, it builds tissues (hair, nails, skin, and muscle) as well protein makes enzymes (which increase the rate of metabolic reactions) and hormones. Protein is also required to make hemoglobin which is needed to transport oxygen to the exercising muscles! If we do not eat enough carbohydrates, we will have to break down protein within body tissues as a source of fuel. This is very inefficient.  When the body has to resort to protein for fuel it will rob the body of protein needed for its many important uses noted above. We must keep the protein available for its other IMPORTANT bodily functions.

Protein has a slow gastric emptying rate (stays in the stomach longer) and therefore is not the food of choice while on the bike (although protein in small quantities in sports drinks is still up for debate). My point is that carbohydrates are king while riding and training! Additionally when protein is burned as fuel it creates excess nitrogen which is excreted in sweat and urine. This results in increased urinary volume and increased dehydration. This is a double negative; inefficient fuel and dehydration. On top of this protein is also “expensive!”

I think it is important at this point to reiterate that protein is NOT a big source of fuel during exercise. Even if you consume more, this will not change. This is science.  “Based on nitrogen balance it can be estimated that protein contributes about 5%-15% to energy expenditure at rest. During exercise, in relative terms more amino acids may be oxidized. In relative terms, however, protein as a fuel is not important because of the much greater increase of carbohydrate and fat oxidation which are your main fuel sources during exercise.  Therefore during prolonged exercise the relative contribution of protein to energy expenditure is usually much lower than it is at rest, usually well BELOW 5%!  In extreme conditions when carbohydrate availability is limited this can rise to   10%”. [ii] Therefore you can see why endurance athletes will not benefit from higher than recommended protein diets. It is important to understand this as many traditional DIET BOOKS are pushing high protein diets. But for these reasons those diets DO NOT WORK FOR ENDURANCE ATHLETES.

The recommended intake of protein for the average person is 0.8g/kg body weight. For endurance athletes, the recommended intake is 1.2 to 1.8g/kg body weight.[iii] Studies show that endurance athletes need 1.2-1.4g/kg body weight to maintain nitrogen balance. In the van Erp-Baart et al study, the highest self reported intakes among athletes was from endurance cyclists who consumed a almost 3g/kg body weight per day. This excess protein will not help these cyclists perform optimally. In fact excess protein is simply stored as extra calories….or fat. On the other hand if you are keeping your energy needs maintained on an excess protein diet this means you are missing out on vital energy sources from carbohydrates and fats. Remember Carbohydrates and Fats ARE YOUR ENERGY SOURCES!

There are two schools of thought. Some scientists feel there is no need to increase protein more than the average person. The other school recommends the range mentioned above 1.2-1.8g/kg. I am of the school that we should intake 1.2-1.8g/kg but sit in the middle of the range. One interesting observation scientists have made is that training seems to have a protein sparing effect in that the better trained an athlete is the less protein oxidation occurs [iv]. This again supports that we do not require excess protein in the diet and may be fine with the amounts recommended to the general population of 0.8g/kg.

To give you a visual idea of what a 1.6g/kg or protein would look like, here is an example of 1.6 grams per kilo for a 165lb athlete:


  • Ex. 165 lb (75kg) athlete in training would eat 120 grams (480cals) of a 3,000-3,500 cal day versus 2000-2500 in carbohydrates.
  • In comparison it is not a large portion of the calories.
  • 120 grams of protein looks like this:
  • 6oz chicken - 40g
  • 2 eggs - 12g
  • 1C plain yogurt - 6g
  • 1 scoop whey protein - 25g
  • 2C black beans and rice - 14g
  • 1C Quinoa - 24g
Having given this example, an athlete would likely need less than what is listed above since there are small amounts of protein in many foods. For example one piece of 100% whole wheat bread has 6 grams of protein, a glass of milk has 8 grams of protein and a cup of oatmeal has 6 grams of protein. Quinoa for example is a grain considered a carbohydrate but has 24grams of protein per cup. It all adds up. This is why it is important to analyze your daily intake in order to not take in excess and be sure to have enough carbohydrates instead.

Even if you increase your protein requirements from the average daily requirement of 0.8g/kg body weight to 1.2-1.8 g/kg it is typically very easy to meet these requirements. In fact chances are you are already eating protein within the endurance athlete recommended range of 1.2-1.8g/kg. Even Tour de France athletes whose diets have been closely followed (some eating 7000-9000 calories a day) are able to meet their protein needs simply due to the increase in overall caloric intake. As noted above we tend to forget that almost all foods have some protein in them.  Generally speaking there is a linear relationship between energy intake and protein intake and if you are matching your energy expenditure for the day you should not have to add protein supplements to your diet. (Having said this protein shakes are often used for convenience more so than for extra protein). Generally speaking getting enough protein from your diet is not a challenge if you are eating properly.

There is a lot of information out there on sports nutrition and a lot of great research that has been ongoing for a long time. This is a well studied and researched area of nutrition. There is no question that the optimal dietary breakdown for endurance athletes is at least 60% carbohydrates, 20-25% fats and 15-20% protein. [v]Trust that you need carbohydrates for fuel, fiber, nutrients and recovery. You need fat for hormones, cell membranes, fuel and to reduce inflammation. You need protein for important bodily functions such as your immune system, tissues, hormones, enzymes and hemoglobin.  Eating high NUTRIENT DENSE FOODS in these proportions is how you will attain optimal performance in tandem with a proper training plan.
The bottom line is; Protein is necessary for the active athlete, but more is not necessarily better. And this is especially so if you replace total caloric needs with protein at the expense of carbohydrates.

The best starting point for you as an athlete is to journal your diet for 3-5 days. Track your macronutrient percentages (carbohydrates, fats, proteins) to make sure you are getting the most from your diet for recovery, performance and overall health. I use Training Peaks Software to track my own and my clients’ dietary intakes. It will break down your daily calories into macronutrients so that you can adjust accordingly either by grams or calories. Pie charts at the bottom of your page show you visual breakdown of your daily caloric intake.  Once you have created a week of meals in the right ratios you will be off to a running start! It can be the difference between being good and being GREAT. If you don’t have the optimal fuel in the tank, you can’t expect the engine to run optimally. Proper sports nutrition can increase your training results dramatically.

We as athletes often undermine all of our hard training by not paying good enough attention to our nutrition. But nutrition is half the recipe to your success!



[i] Ryan, Monique. Sports Nutrition for Endurance Athletes-Second Edition. Velo Press, March 2007
[ii] (Jeukenrup, Asker. Gleeson, Michael. Sport Nutrition-Second Edition.  Champaign, IL; Versa Press, 2010.)
[iii] (Jeukenrup, Asker. Gleeson, Michael. Sport Nutrition-Second Edition.  Champaign, IL; Versa Press, 2010.)
[iv] (Butterfield et al 1984) (Phillips et al. 1999)
[v] Ryan, Monique. Sports Nutrition for Endurance Athletes-Second Edition. Velo Press, March 2007

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