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Staying on the subject of proteins, continuing the discussion on the protein needs of athletes, but broadening the context a bit, in today's and future texts I would like to provide you with some information on the issue of protein portioning throughout the day, as well as offer some sample meals rich in protein.
There has been quite a lot of research on proteins (quite is probably an understatement), less on active people, but we still have a large body of literature to which we can refer, debunking a considerable number of myths that have accumulated around the good old "protein" and correcting false beliefs.
Maximum 20g of protein per meal?
It has become common knowledge that 20 or 30 grams of protein (depending on the “source”) should be the absolute maximum consumed in one meal. The arguments vary – the inability to digest a larger amount, “rotting” of protein products in the intestines, various clinical conditions and other, more or less rational speculations. Scientists come to our rescue in this matter in the form of human studies – a group of women consuming the entire daily protein requirement (1.7 g/kg of lean body mass) in one meal was compared with those consuming it in 4 meals. It turned out that neither the body composition nor the nitrogen balance in both groups were significantly different. While the issue of body composition can be considered somewhat controversial (in the case of the above groups, the problematic factor could have been the consumption of too low a portion of leucine – more on that later), the nitrogen balance itself tells us a lot about the absorption and use of proteins. Theories about the inability to digest (ever) protein in quantities greater than the "ridiculous" 20g are so bizarre because it is impossible to imagine digestion as an immediate process - occurring only immediately after eating food. It is a practically constant process, taking up a lot of time and energy for our body - hence - eating hard to digest / long-sitting / large amounts of food prolongs the digestion process, which of course does not have to be comfortable or healthy in the long run, but it does not make it absolutely impossible.
Whey on top – the leucine threshold under the microscope
The concept of the leucine threshold is relatively new, but very hotly debated by both scientists and the mass media. The aforementioned threshold is defined as the amount of a key amino acid (leucine), which is to maximize the activity of muscle synthesis proteins to the greatest possible extent. Further elevation of the leucine level does not bring additional benefits (in the context of MPS activation). However, this threshold is not a constant value, and the age and condition of our body (lack of co-occurring diseases, good condition of systems) have a decisive influence, as well as the physical activity used.
It is worth mentioning that the literature emphasizes the lack of additional benefits (in the context of MPS stimulation) in connection with the addition of carbohydrates to a protein portion that increases MPS to maximum values. Of course, this does not mean that the use of carbohydrates after training (or at any other time of day) is unjustified, it is not! Their addition will simply support the processes of rebuilding the body's energy resources (with an emphasis on glycogen), improve the palatability and satiety of the meal, but will not directly affect the increase in muscle synthesis activity.
In the light of this theory, it is not the total protein supply but the dose of leucine that would be the basic determinant of muscle development.
Unfortunately (or fortunately), further studies have yielded slightly different results. It turned out that yes – leucine is the most important activator of the MPS process, but when it occurs in the “company” of other amino acids – this effect is intensified. Hence the strong bow of the sports and scientific communities towards complete proteins with high biological value and high leucine content – for this very reason, the most optimal protein supplement for an athlete seems to be WPC, i.e. whey protein concentrate.
So how much protein in a meal? - One dose at a time
It is postulated that the dose of protein taken after exercise (after resistance exercise, although it will most likely be appropriate after aerobic exercise), i.e. at the time of the body's greatest demand for this macronutrient, and at the time when we care most about stimulating the process of muscle fiber development, in isolated form (e.g. as a supplement) should reach 0.25-0.3g/kg of the athlete's body weight, which is usually averaged to 20-25g/portion (we are talking about protein of high biological value). However, recent studies have brought information that this value is largely dependent on the number of muscle fibers activated by exercise, so adepts undergoing comprehensive training - the whole body in one training unit - will benefit more from consuming a higher dose - here the proposed 40g of protein/portion is.
It is also believed that the strongest anabolic potential of whey protein (popular whey), superior to casein proteins or SPI (soy protein isolate), results from its high leucine content and high bioavailability of amino acids derived from it, as well as the relatively quick process of its digestion, absorption, and ultimately use by the body.
Another myth that needs to be debunked (with a heavy heart) is the use of arginine and glutamine as powerful anabolics – unfortunately, their use does not affect the maximization of the MPS process (muscle protein synthesis). So let's remember – to improve the comfort of sleep or "bedtime" – arginine can definitely be used, to improve immunity and feed enterocytes – glutamine will do, but as anabolics – we say no to them!
Black clouds also hang over the popular BCAAs – they are not worthless, but their usefulness is limited. It is not a miraculous anti-catabolic as it is commonly believed, but it can find its application, one of them being, for example, adding a drink with BCAA to a meal slightly poorer in protein, to maintain high MPS activity! About other possible applications of glutamine, arginine or BCAA – another time!
That's all for today, in the next entry I will try to provide you with a few sample meals that meet both the 25 and 40g of protein/portion assumptions, as well as propose an all-day menu.
Literature:
- Arnal M. Mosoni L., Boirie Y. et al.: Protein pulse feeding improves protein retention in elderly women. Am J Clin Nutr. 1999, 69, 6, 1202-1208.
- Arnal M., Mosoni L., Boirie Y. et al.: Protein feeding pattern does not affect protein retention in young women. J Nutr. 2000, 130, 7, 1700-1704.
- Joy J., Lowery R., Wilson J. et al.: The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutr J. 2013, 12, 86.
- Phillips S.: a brief review of critical processes in exercise-induced muscular hypertrophy. SportsMed. 2014, 44, 1, 74-77.
- Churchward-Venne T., Burd N., Mitchel C. et al.: Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 2012, 1, 590, 11, 2751-2765
- Macnaughton L., Wardle S., Witard O.: The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein. Physiol Rep. 2016, 4, 15, e12893.
- Wolfe R.: Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017, 14, 30
Paweł Szewczyk - Master of Dietetics specializing in sports nutrition. Dietician of Polish National Team and European Champions. Participant and speaker at trainings, conferences and seminars throughout the country. Lecturer at the State Medical Higher Vocational School in Opole and the Institute of Psychodietetics in Wrocław. On a daily basis, he deals with professional counseling in the field of nutrition and supplementation, publishes scientifically and popularly, and trains athletes and dieticians.
Author of the blog: szewczykpassion.wordpress.com
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