For the majority of strength athletes, gym goers and exercise enthusiasts, protein will always be the number one macronutrient due to its enhancing effects on muscle protein synthesis (that’s gainz to you, bro!)
There have been a number of recent news stories warning of the dangers of eating too much protein and suggesting that we have become obsessed with this particular macronutrient. (Remember when fat was the dietary whipping boy?)
These stories have linked excess protein with nausea, kidney stones, osteoporosis, diabetes and cancer, but it’s not entirely clear if they are the result of the protein itself or, for example, the saturated fat or salt in the foods that contain the protein, such as cooked or processed meats.
While the list of dangers are sobering, the problem with so much food research is that it is usually done on sedentary populations who, let’s face it, suffer the gamut of health problems from doing too little and eating too much of just about everything.
So what exactly is ‘high protein’ and for whom might there be benefits?
The UK recommendation for protein is 0.75 grams per kilograms of body mass per day (g/kg/d), which equates, on average, to around 55g for men and 45g for women.
However, it’s universally agreed that regular exercisers, particularly those involved in strength sports and resistance training require a much higher protein intake than the baseline in order to effectively support their activity demands and fuel increases in muscle mass.
This is especially true when people are following a calorie-restricted diet in an attempt to reduce body fat because a calorie deficit increases the likelihood of losses in lean tissue, something we see at Bodyscan every day.
It has previously been thought that individuals pursuing strength activities, such as lifting weights, should be consuming between 1.5-2g/kg/d of protein in order to meet the protein requirements of the exercise activity and promote optimal muscle protein synthesis. Other research claims that 2g/kg/d is the ‘maximally beneficial’ limit of protein intake and any more provides no extra benefit in terms of body composition and strength. Indeed, the extra calories provided by the excess protein have been assumed to have a negative effect on body composition (ie, an increase in body fat).
However, recent research looking into daily protein requirements for resistance-trained individuals suggest that 2g/kg/d is not the upper limit. Far from it.
American studies led by Dr Jose Antonio suggest that protein intakes of above 3g/kg/d appear to increase fat-free mass and strength, with a simultaneous decrease in fat mass when compared to lower intakes (between 1.8-2.6g/kg/d).
Chronic high protein ingestion of 3.3g/kg/d for six months has been shown to have no negative effects in terms of fat gain or kidney function when compared to a lower intake of 2.5g/kg/d. Even a hyper-energetic diet consisting of more than 4g/kg/d (5.5x greater than the recommended daily amount) had no negative effects and did not result in significant negative changes over time or between groups for total body mass, fat mass, fat-free mass, or percentage body fat, when compared to a lower protein control group (consuming 1.8g/kg/d). This was despite the high protein group consuming significantly more protein and calories than the control group for a period of eight weeks.
Consequently, these recent findings seem to suggest that it is beneficial to consume protein amounts higher than 2g/kg/d, especially when calories are restricted, as the research shows improved preservation of muscle tissue combined with greater reduction or minimal gains in fat from intakes of more than 2g/kg/d.
These emerging findings suggest that for non-sedentary populations, and in particular strength-trained athletes, 2g/kg/g could actually be the floor, rather than the cap, for protein intake, especially when gains in lean mass are the primary focus.
You may like to check out a further discussion of protein requirements and a protein calculator at Fitness Savvy.