Firstly, we need to establish the recommended daily allowance advised to sustain a balance of protein synthesis versus degradation in health adults, to account for differences in protein metabolism and nitrogen losses (via urination and excretion).
This value is 0.8g per kg of bodyweight daily (35), which for an average 80kg man would be:
0.8g x 80kg bodyweight = 64g per day
This value is suggested to cover 97.5% of healthy men and women over the age of 19 years old. However, it is also advised that the cost of exercising in regards to protein metabolism will be greater in those who exercise and require more protein to allow lean tissue development and repair post training (36,68). In fact the predominant nutritional guidelines for protein consumption suggest that for physically active people up to 2g per kg per day is both safe and more effective post training (13).
Such guidelines also suggest that whilst every step should be taken to obtain protein via whole foods in the diet, protein supplementation through sources such as whey, is an effective and efficient way of making sure protein intake is met (13).
For the purposes of clarity we will now outline the proposed dosage recommendations for varied forms of activity and exercise, as each will predispose the participant to different physical stressors which may require a different amount of protein consumption.
Whey Dosage For Endurance Athletes:
Generally protein intake should range from 1g/ kg to 1.6g/ kg depending upon the duration and intensity of performance (27,43,49,69).
The advised dosage for 2 bouts of 90 minutes cycling at 46% VO2 max was 1g per kg per day (21).
A dosage of 1.6g per kg per day meets the protein (nitrogen balance) requirements for experienced runners (70).
In an elite running population this requirement is suggested to reduce to 1.49g per kg per day (25).
Whey Dosage For Strength Training:
It is likely obvious to most that activities involving strength, such as weight lifting and bodybuilding have a higher protein requirement than endurance activities. This is particularly evident when undertaking the early stages of training or when volume of exercise changes dramatically.
However, the scientific literature does not have a specific dosage which is more commonly quoted for this population. Rather a range of protein consumption levels are usually seen.
1.2-1.8g per kg per day is suggested to stimulate lean muscle mass accretion (1,16,38,42,69-70). This same dosage (1.2-1.8g) will facilitate adaptations to training if sufficient calories are provided also (57-58,65,71,75-76,80).
Body builders are suggested to consume 1.12g per kg per day specifically (70). Power sport athletes (such as Olympic weight lifting) are suggested to consume between 1.6-2g per kg per day (2,36,42,44,69).
Doses of 2.3-3.1g per kg per day are suggested for bodybuilders (31) as a higher intake is proposed to sustain lean body mass (LBM), with sufficient carbohydrates and reduced fat intake (30,50,). Intense resistance training (alongside calorie restriction) can lead to a negative nitrogen balance (NNB) despite 2g/kg protein consumed (12,15).