It’s the age-old question: How much protein does your body REALLY need to build that desired lean muscle?
The standard advice you’ve probably heard around your local gym, or from your personal trainer has always been about 1.5 grams of protein/kg of body weight (BW). But does this bro-science have any merit?
Within the fitness community, at your local boot-camp, gym, sports club or your favourite youtube channel, you will hear people advocating for above 3 grams of protein per kg of BW, and you’ll come across people who claim they continue to build strength and lean muscle on 1 gram/kg or less.
In this article, I break down relevant research and science to settle this debate once and for all.
If you need a refresher on total calorie consumption read this: CALORIES: What are they and why do we need them??
The Recommended Daily Intake
For adults between the ages of 19-30 years old, The Australian Health & Medical Research Council recommends 0.68g/kg for males and 0.60g/kg for females. For many of you, this number will seem exceptionally low, and it is.
Here is an example using 65kg women with a daily goal of 1700 calories to show how it is.
65kg X 0.60 of protein = 39g per day. If she consumes 1700 calories per day, only 9.18% of her daily calories come from protein. Leaving 90% to come from carbohydrates and fats.
In a separate article by the Australia Health & Medical Research Council, they recommend intakes at or above 15% protein appear to be required for ensuring that the estimated average requirement for micronutrients are met.
Research by The Sports Nutrition Society recommends 0.8 grams/kg BW for 95% of the population. They have obtained this figure through the nitrogen balance technique. Although this method is the most common, most researched and at the time of writing this article, the best method of measurement, there are some problems associated with this technique in both athletic and non-athletic populations. Some experts suggest that nitrogen losses through gas, excessive sweating, and high rates of ventilation during training can make measuring nitrogen measurement almost impossible, leading to false results. If this is the case, then the recommended protein intake for maintenance of muscle tissue may be underestimated.
It is also important to recognise that these minimum protein requirements are not equivalent to optimal protein levels. They are purely a minimum amount to avoid muscle tissue catabolism.
Increasing your protein
There has been debate among athletes and nutritionists regarding dietary protein needs for centuries. Although contrary to traditional belief, recent scientific information collected on physically active individuals tends to indicate that regular exercise increases daily protein requirements. This may mean that actual requirements are below what is needed to optimize athletic performance. and so the debate continues.
Numerous interacting factors including energy intake, carbohydrate availability, exercise intensity, duration and type, dietary protein quality, training history, gender, age, timing of nutrient intake and the like make this topic extremely complex. At the present time, substantial data indicate that the current recommended protein intake should be adjusted upward for those who are physically active, especially in populations whose needs are elevated for other reasons, e.g., growing individuals, dieters, vegetarians, individuals with muscle disease-induced weakness and the elderly.
Endurance Athletes, Body Builders & Resistance Trainers
A study in the Journal of Applied Physiology examined the effects of training on nitrogen balance and body composition during periods of habitual and altered protein intakes. They conclude that resistance trainers and bodybuilders during habitual training require a daily protein intake greater than that for sedentary individuals in the maintenance of lean body mass and that endurance athletes require daily protein intakes greater than either bodybuilders, resistance trainers or sedentary individuals to meet the needs of protein catabolism during exercise.
Optimal Timing of Protein Ingestion Relative to Exercise
In 2001 a perspectives paper entitled “Grandad, it ain’t what you eat, it depends when you eat it – that’s how muscles grow! was submitted. The paper was a brief review of a earlier study that investigated the effect of immediate and 2 hour delayed feedings of protein on muscular hypertrophy and strength over a 12 week period of resistance training in elderly males. An oral supplement of 10 grams of protein, 7 grams of carbohydrate, and 3 grams of fat was administered. Results indicated that muscle fibers in the quadriceps increased in the immediate protein condition, where as no significant increases were found in the 2 hour delay condition. Both dynamic and isokinetic strength increased, by 46 and 15%, respectively in the immediate condition, whereas the delayed condition only improved in dynamic strength, by 36%.
These results indicate that immediate intake of protein after exercise is an important factor regulating muscle growth. Possible explanations include the observation that protein synthesis is stimulated in response to resistance training, and these effects are inversely related to time, as seen in Figure 1 below.
Strength And Performance
A study published in the Medicine & Science in Sports & Exercise investigated the effect of a high protein diet (2 grams/kg BW) and a relatively lower protein diet (1.24 grams/kg BW) on bench press 1- Rep Max (RM) and squat 1-RM performance during a 12 week resistance training program in experienced resistance trained participants. While there was minimal difference for bench press, the high protein group improved their 1-RM squat to a greater extent than the low protein group.
In a similar study divided 51 male and female participants into two groups. Group one received a 40 gram whey protein supplement twice daily, while group two received a carbohydrate placebo during a six month resistance training program. Participants in the supplemented group averaged twice the protein intake (2.2 g/kg body weight) as the placebo group (1.1 g/kg body weight). The protein supplemented group experienced significantly greater strength gains than the placebo group in bench press and hip sled tasks, as seen in figure 2.
What does this all mean
To summarise I will combine all the given information from a range of articles, and from my personal experience.
For an average Jane, who does not participate in any sort of serious exercise activities, the recommended amount of 0.8grams/kg BW by The Sports Nutrition Society is sufficient in maintaining a healthy weight and keeping muscle catabolism to a minimum. With this amount of protein, growing lean muscle mass and increasing strength will be extremely difficult. For those participating in steady, medium intensity cardio programs 0.8grams per kilogram is a sufficient dose for those activities.
For someone who regularly engages in resistance training with the goals of increasing lean muscle mass and increasing strength, the recommended amounts are between 1.5 – 2 grams per kilogram of body weight. It turns out science backs up the bro-science from your local gym bodybuilder. This amount will not only ensure you maintain your hard earned muscle but that your strength is consistently increasing and you are able to continue to grow new lean muscle.
Is there a maximum consumption limit
For those that wonder if there is a limit to the amount of protein you can consume per day, the answer, at this point is no. According to the Australian Health & Medical Research Council, there is limited data available on maximum protein intakes, it is impossible to set an upper limit in terms of grams per day. They are unable to establish a maximum limit at which adverse health consequences occur.
My personal recommendations
I personally aim for around 30-40% of my daily calories to come from protein sources. Consuming as much protein throughout the day through lean sources, such as fish, lean mince and turkey. I also supplement with Whey Protein powder post workout and throughout the day to boost my daily levels if I have not consumed sufficient amounts throughout the day through food sources.
If you are going to supplement with protein powders, I highly recommend using an Australian brand that sources their ingredients from local producers and uses Australian or New Zealand grass-fed dairy. For a good quality WPI, the protein per 100g should be upward of 85, meaning many of the fats, carbs & sugars have been filtered out. You can also buy many Australian WPI’s that are both lactose and gluten free for people with allergies. Remember to always check the ingredients list and nutritional table (not just protein, but everything you eat) and aim for a protein powder with less than 5 ingredients. You don’t want to be buying a protein with 15 ingredients, including added salts, thickeners, creamer from sunflower oils and corn syrups.
If you have any questions about your daily protein intake and/or supplement program you can email me anytime.