If you skim through a body building magazine, talk to someone in the gym, or conduct an online search for protein you will be inundated with information. Some if not most may be inaccurate but how do you decipher what is true? This article will outline protein sources to include the recommended quantity, timing and quality.
First let’s discuss some background information on protein. Protein is the building blocks for the bones, muscles, cartilage and skin and is also essential for maintaining cellular integrity and function (1). Protein is made up twenty amino acids, nine of which are considered essential. Essential amino acids are ones the body cannot make so they must be acquired through food sources which can be found in animal food sources such as meat, fish, eggs and milk or vegetarian food sources such as grains, legumes, seeds and beans. Different types of protein have shown to provide a faster recovery response post workout that I’ll discuss later in the article.
According to the Institute of Medicine Food and Nutrition Board, the recommended daily allowance (RDA) for protein for both men and women is 0.8 grams per kilogram body weight per day (1). The 2010 Dietary Guideline for Americans* state the daily recommended intake (DRI) for protein to be 10 to 35 percent of total calorie intake. In my opinion the RDA is excessively low when considering athletes and the DRI is too broad of a range especially if you are trying to dial in on your macronutrient needs, i.e. macronutrients are your carbohydrates, protein and fat. So how do you know how much you need? Digging deeper and coming to a more accurate response, in a 2009 Position Stand of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance, the recommended protein intake for athletes is 1.2 to 1.7 grams per kilogram body weight per day (2). The position stand notes the RDA and DRI do not take into account the specific needs of athletes which I completely agree with. The following is their recommendation for different types of athletes:
- Endurance athletes: 1.2 to 1.4 grams per kilogram body weight per day
- Strength Training: 1.2 to 1.7 grams per kilogram body weight per day
For example: A 165 pound (75 kilogram) endurance athlete would need 90 to 105 grams of protein per day OR the same weight athlete who was strength training would need 90 to 127 grams of protein per day. Both of these instances are well over the RDA of a calculated 60 grams per day (0.8 grams X 75 kilograms = 60 grams).
Quantity and Timing of Protein Intake
This is all great information but what about specific timing of protein intake? I get this question a lot… how much post workout or how much during the day at each meal should I consume? I recommend a minimum of 20 grams of protein post workout. Research has shown that this amount illicits the leucine response and stimulates muscle protein synthesis (3). More specifically, protein intake for athletes includes (3):
- Four equally spaced meals containing protein,
- Three meals should be 0.25 to 0.3 grams per kilogram per body weight
- A larger pre-sleep meal with protein intake at 0.6 grams per kilogram body weight
For example, let’s take a look at the 165 pound (75 kilogram) athlete. The protein intake would be to 18 to 22 grams at three meals with a larger intake of 45 grams of protein before bed. Total protein intake for the day would be 99 to 111 grams. This falls in the range of the 1.2 to 1.7 grams per kilogram per day in the example shown above. One minor exception, as stated above, I would recommend at least 20 grams of protein within 30 minutes after each workout because of the leucine response. For those who need more, the same leucine response has been found when consuming up to 40 grams of protein post workout. It has been shown that in elderly men, 40 grams of protein post workout is essential for muscle synthesis (3). The consumption of a minimum of 20 grams post workout recommendation would be across the board for any athlete, regardless of weight and gender.
Quality of Protein Intake
I’ve discussed timing and quantity of protein intake but now let’s take a look at quality. Not all protein is created equal especially for athletes and their recovery. Specifically whey protein produces a greater increase of muscle protein synthesis. Whey protein contains all 20 amino acids including the three branch chain amino acids leucine, isoleucine and valine which can be oxidized by muscled during exercise. The term “branch-chain” is the chemical structure of these amino acids. During recovery, due to the leucine content of whey, protein muscle synthesis is increased. Whey is more effective than soy which is more effective than casein protein sources (3). Lean body mass gains are seen with the ingestion of whey protein due to the leucine response. Whey is higher in leucine and is absorbed more quickly post workout. The ideal protein dose post workout to elicit the leucine response is 20 grams (3). The best whey protein source comes from diary. An inexpensive source of 20 grams of protein is 20 ounces of chocolate milk and a banana. While food sources of protein are best, protein powders can work but you have to be careful of the type of protein powder and what other "junk" is added to the product.
I’ve seen many athletes who are trying to achieve a specific weight especially in endurance events. I myself know that I can run faster and with less pain if I am even 5 pounds lighter come race day. Based on personal experience I’ve cut back on food intake but lost lean muscle in the process. I came across a study looking at protein intake in women who are trying to lose weight. Research has found that increased protein intake, specifically through dairy during weight loss spares lean muscle mass while decreasing fat mass (4,5). When I work with athletes looking lose weight, I stick to the equally spaced protein at each meal and a bolus before bed as discussed earlier in the article.
Overall, the main things to keep in mind with protein intake:
- Consistent timing and quantity is important for athletes and in weight loss.
- Post workout consumption of at least 20 grams of whey protein will stimulate a leucine response and protein muscle synthesis.
While this article focuses on protein intake, athletes still need adequate carbohydrate intake for performance and recovery. I’ll look more into carbohydrate intake and research on timing and quantity in the near future.
*The 2015 Dietary Guidelines Americans will be released this fall
- Institute of Medicine, Food and Nutrition Board. (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Retrieved June 15, 2015, from http://www.nap.edu/catalog/10490/dietary-reference-intakes-for-energy-carbohydrate-fiber-fat-fatty-acids-cholesterol-protein-and-amino-acids-macronutrients.
- Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. J Am Diet Assoc.2009; 109(3):509-527.
- Phillips, Stuart. (2012). The Importance of Dietary Protein in Resistance Exercise-Induced Adaptation: All Proteins Are Not Created Equal. [PowerPoint slides]. Retrieved from http://scan-dpg.s3.amazonaws.com/resources/DOCS/webinars/2012_The_Importance_of_Dietary_Protein_in_Resistance_Exercise_Induced_Adaptation_webinar.pdf.
- Josse AR, Atkinson SA, Tarnopolsky MA, Phillips SM. Diets higher in dairy foods and dietary protein support bone health during diet- and exercise-induced weight loss in overweight and obese premenopausal women. J Clin Endocrinol Metab. 2012 Jan;97(1):251-60. doi: 10.1210/jc.2011-2165. Epub 2011 Nov 2.
- Josse AR, Atkinson SA, Tarnopolsky MA, Phillips SM. Increased consumption of dairy foods and protein during diet- and exercise-induced weight loss promotes fat mass loss and lean mass gain in overweight and obese premenopausal women. J Nutr. 2011 Sep;141(9):1626-34. doi: 10.3945/jn.111.141028. Epub 2011 Jul 20.