# Protein Requirements



## AChappell (Jun 1, 2011)

A little article I put together.

*Protein Requirements for Athletic Populations*

Andrew Chappell BSc (Hons), MSc, PhD Nutritional Science

Protein requirements for athletic populations is one of the most studied and exciting subjects in sport and exercises nutrition. The current guidelines for sedentary untrained individuals set by the Scientific Advisory Commission on Nutrition (SACN) remain relatively low for males and females at less than 60g per day or around 10% of a person's total energy intake. These levels are based on the minimum required to prevent deficiency diseases and should not be considered optimal in athletic populations.

We currently know that endurance based athletes have different protein requirements (0.8-1.4g/kg bodyweight ACSM) compared to strength trained athlete's involved in power sports like sprinting, Olympic weightlifting, bodybuilding or shot put etc. This article will predominantly focus on protein requirements within strength trained populations.

So how much protein should you consume? The current guidelines from the American College of Sports Medicine (ACSM) recommends between 1.2 - 1.7g/kg of body weight, so for the 70kg man that's between 84 - 119g per day which is hardly excessive. The current position stance from the International Society of Sports Nutrition (JISSN) recommends intakes between 1.4 - 2.0g/kg bodyweight, so for the same 70kg athlete that would be between 98 - 140g per day (Kreider et al . 2010). Again such intakes within athletic populations would hardly be considered excessive and anecdotal reports of between 400- 600g of protein per day are not uncommon. A recent review by Helms et al. (2014) suggests that 1.8 - 2.7g/ kg bodyweight maybe optimal to build lean body mass, however where athletes are on calorie restricted diets intakes of up to 2.3 - 3.1g/kg bodyweight may be optimal. With so many conflicting reports within the scientific community it's easy to see why there is confusion about protein requirements for strength and power athletes.

There does appear to be at least an upper limit when it comes to protein consumption. A recent study found that high protein intakes (4.4g/kg/bodyweight) did not translate into increased muscle mass compared to lower intakes (2.7g/kg/bodyweight). Interestingly despite the extra calories the high intake group did not increase bodyfat (Antonio et al. 2014). So erring on the side of caution and choosing to consume an upper limit for protein nutrition might be better than under consuming a low protein intake and diminishing any potential gains. Fad diets like the Atkins and Paleo diet further confuse matters where individuals may consume as much as 40 - 50% of their daily calorie intakes from protein alone. Nutrient timing strategies proposed by Norton & Wilson (2009) and followed up by Areta (2013) in human studies have shown that intakes of 120g are enough to maximise protein synthesis when protein meals are equally distributed across the day in 20g amounts. Intakes of the other macronutrients fats and carbohydrates may also be equally important and may actually reduce an athlete's protein requirements when in an energy surplus.

Based on the current evidence it remains clear that when an athlete is dieting, protein requirements should be higher in order to preserve lean muscle mass while meal timing may be an effective strategy to help preserve lean bodymass, something bodybuilders have done for years. So protein intakes of between 2.3- 3.1g/kg bodyweight should be used while dieting. These days when dieting I use the lower end of the scale with nutrient timing strategies so I can consume more carbohydrates and train harder while still preserving lean mass. Through experience I opt for levels around 1.8g/kg bodyweight while dieting. While training in the offseason where calories are abundant I would always recommend even lower intakes between 1.2- 1.7g/kg bodyweight with a greater emphasis on carbohydrates than protein. However requirements should be tailored to the individual and some are more carbohydrate sensitive than others, so intakes should be adjusted accordingly.

Take home points:

Protein intakes between 2.3- 3.1g/kg/ bodyweight may be ideal in preventing the loss of muscle during a calorie deficit.

Protein intakes between 1.8 - 2.7g/kg/bodweight may help build lean muscle mass where calories are abundant.

References

ACSM Position Stance: Nutrition and Athletic Performance.

Kreider et al. (2010) ISSN Exercise & sport nutrition review: research and recommendations. JISSN. Position Stance.

Helms et al. (2014) Evidence based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. JISSN.

Antonio et al. (2014) The effects of consuming a high protein diet (4.4g/kg/bw) on body composition in resistance-trained individuals. JISSN.

Norton and Wilson (2009) Optimal protein intake to maximize muscle protein synthesis: examination of optimal meal protein intake. Agro Food Industry Hi Tech.

Areta (2013) Timing and Distribution of protein ingestion during prolonged recovery from resistance exercises alters myofibrillar protein synthesis. J physiology.


----------



## XL BODIES LTD (Nov 25, 2005)

Good post Andy, we need more of these, keep them coming fella


----------

