This article was written by our regular contributor; dietitian – Maeve Hanan.
Although protein gets a lot of attention in the health and wellness space, there are a lot of mixed messages surrounding this nutrient. This article will debunk 6 common myths about protein.
Myth 1: You only need to worry about protein if you workout
This is absolutely not true, protein is required to support a wide range of body functions, regardless of exercise status, including; bone and muscle mass, hormone and enzyme function, antibodies for immunity, and skin health. However, to get the most out of workouts the amount and distribution of protein across the day is important to pay attention to. Those who exercise regularly are advised to consume 1.4-2g of protein per kg bodyweight per day consumed as 20-40g every 3 to 4 hours across the day, as compared with the recommendation of 0.75g of protein per kg per day for the general public (1, 2).
Myth 2: Protein is harmful to your kidneys
People with liver and kidney disease may be advised to follow a low protein diet (with appropriate medical and dietetic support). However, for the general healthy population and athletes consuming a high protein diet has not been demonstrated as being harmful to the kidneys (1, 3). In fact, studies have found that resistance training adults who consumed upto 4.4g of protein per kg per day for 8 weeks or 2.5g/kg/day for a year for adults had no harmful effects on kidney health (4, 5).
Myth 3: Protein weakens your bones
This myth comes from the alkaline diet ‘theory’ that high-protein foods are acidic and consuming these causes calcium to leach from the bones and be excreted in urine. The alkaline diet is not backed by research and has been thoroughly debunked, as the body tightly regulates pH balance. In reality, protein is vital for strong and healthy bones — in fact roughly 50% of our bones are made up of protein! (6). Although there is some mixed evidence about the impact of protein on bone health (7), clinical studies tend to find that high protein foods have an unharmful or positive impact on bone health as long as calcium intake is sufficient (8). For example, systematic review from the National Osteoporosis Society in 2017 found that higher protein intakes were not linked with worsening bone health, and some improvements in bone mineral density were seen; although the researchers acknowledged that more high-quality and long-term studies are needed (9). A more recent review concluded that consuming more protein than the current recommended daily amount may reduce fracture risk and improve bone mineral density for older adults (10).
Myth 4: Vegans and vegetarian don’t get enough protein
Although vegans and vegetarians generally consume less protein than those who consume animal-based products, they tend to meet the recommended amount for the general population of 0.75g/kg/day (11). However, this may be more of a challenge for older adults and athletes who have higher protein needs (1, 11). In fact, plant-based athletes are recommended to consume roughly 10% more protein than non-vegetarians due to differences in the digestibility of plant-based proteins (12, 13). For most vegans and vegetarians it is more of a priority to make sure that they are consuming a variety of protein sources across the day, as most plant-based protein sources contain lower amounts of one or more essential amino acid (i.e. amino acids the body can’t produce by itself) (11, 14). For example, pulses are lower in methionine and grains are lower in lysine.
Myth 5: The more protein, the better when it comes to building muscle
Consuming 20-40g of protein (or 0.25g/kg) every 3-4 hours is recommended to maximise muscle building, particularly for athletes and those who exercise regularly (1, 15, 16). A small study from the US investigated the impact of consuming 70g of protein after resistance training and found no further benefit in terms of muscle gain (as compared with consuming 40g of protein); but they did find a reduction in protein breakdown (1, 17). Overall, the 20-40g protein hits regularly throughout the day seems to be the best option for building muscle, rather than consuming megadoses of protein.
Myth 6: You need protein ASAP after a workout
Consuming protein after workouts is important for muscle muscle recovery and muscle building. But this doesn’t need to be immediately after exercise as muscle building peaks within 3 hours of exercise, and remains raised for at least 24 hours (1). This brings us back to the recommended 20-40g of protein within 2-4 hours of exercise (1). Consuming protein along with carbohydrate before exercise has also been found to be beneficial (18). Overall, the total daily intake and spread of protein across the day seems to be more important than consuming protein straight after a workout. The type of protein consumed is also important, as our body needs enough essential amino acids, including an amino called leucine, to optimise muscle growth and recovery (1).
- Jäger et al. (2017) “International Society of Sports Nutrition Position Stand: protein and exercise” [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/28642676]
- British Nutrition Foundation (2019) “Nutrition requirements” [accessed July 2021 via: https://www.nutrition.org.uk/healthyliving/resources/nutritionrequirements.html]
- WHO (2007) “Protein and Amino Acid Requirements in Human Nutrition” [accessed July 2021 via: https://apps.who.int/iris/bitstream/handle/10665/43411/WHO_TRS_935_eng.pdf?sequence=1&isAllowed=y]
- Antonio et al. (2016) “A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males” [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/27807480/]
- Antonio et al. (2014) “The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals” [accessed July 2021 via: https://jissn.biomedcentral.com/articles/10.1186/1550-2783-11-19]
- Heaney & Layman (2008) “Amount and type of protein influences bone health” [accessed July 2021 via: https://academic.oup.com/ajcn/article/87/5/1567S/4650438]
- Darling et al. (2021) “Dietary protein and bone health: towards a synthesised view” [accessed July 2021 via: https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/dietary-protein-and-bone-health-towards-a-synthesised-view/EB7D2F09B15A6F85FED2169249457741]
- Rizzoli et al. (2018) “Benefits and safety of dietary protein for bone health—an expert consensus paper endorsed by the European Society for Clinical and Economical Aspects of Osteopororosis, Osteoarthritis, and Musculoskeletal Diseases and by the International Osteoporosis Foundation” [accessed July 2021 via: https://link.springer.com/article/10.1007/s00198-018-4534-5]
- Shams-White et al. (2017) “Dietary protein and bone health: a systematic review and meta-analysis from the National Osteoporosis Foundation” [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/28404575/]
- Groenendijk et al. (2019) “High Versus low Dietary Protein Intake and Bone Health in Older Adults: a Systematic Review and Meta-Analysis” [accessed July 2021 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6704341/]
- Mariotti & Gardner (2019) “Dietary Protein and Amino Acids in Vegetarian Diets-A Review” [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/31690027/]
- American Dietetic Association (2009) “American College of Sports Medicine position stand. Nutrition and athletic performance” [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/19225360]
- Ciuris et al. (2019) “A Comparison of Dietary Protein Digestibility, Based on DIAAS Scoring, in Vegetarian and Non-Vegetarian Athletes” [accessed July 2021 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6950041/]
- Barr & Rideout (2004) “Nutritional considerations for vegetarian athletes” [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/15212753/]
- Witard et al. (2014) Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/24257722/]
- Macnaughton et al. (2016) The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein. [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/27511985/]
- Kim et al. (2016) The anabolic response to a meal containing different amounts of protein is not limited by the maximal stimulation of protein synthesis in healthy young adults. [accessed July 2021 via: https://pubmed.ncbi.nlm.nih.gov/26530155/]
- Ormsbee et al. (2014) “Pre-Exercise Nutrition: The Role of Macronutrients, Modified Starches and Supplements on Metabolism and Endurance Performance” [accessed July 2021 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4042570/]