Dietary Protein Intake How Much is Enough

Dietary protein from foods serves as a building block for all human body tissues. Consuming enough protein is therefore important for healthy formation and renewal of all body cells. Depending on the health condition and activity pattern the protein intake requirement might vary from person to person. For instance when recovering from an illness or injury, or when exercising or playing a sport, the need for protein is higher because the body actively works on rebuilding the tissue. In case of increased medical need a clinical dietitian can guide patients to reach optimal intake. With sports nutrition the case is a bit different. Ideally also a dietitian or a sport nutrition coach could help out, but this service is much underused because of the costs and wide accessibility of sports nutrition information on the Internet. However sports forums and blogs vary in the recommendations. Some also promote the use of sport drinks, shakes, powders and bars. Research shows that there are also adverse health effects of exceeding the recommended daily protein intake.¹ It is therefore important to communicate the right information about the daily individual body needs for protein, use of protein rich products and the possible adverse effects of protein additives.

How much is enough?
The medical guideline for protein intake by healthy adults is 0.8g per kilogram of body weight a day (g/kg), which equals 10–15 percent of the total daily energy intake (En%).^2,3 The amount can easily be fulfilled with normal foods like milk and meat (products), fish, nuts and grains. A healthy adult of about 70 kilograms needs 56 grams of protein daily (weight*0.8). From table 1 we see that by having a healthy breakfast, lunch, and dinner this intake amount can be reached. Most people in western countries in fact exceed this consumption amount already by eating their normal daily diet.³ Due to loss of muscle tone with age the need for protein intake can increase with ageing.⁴ Research shows that in combination with physical activity, increased protein intake of 1.0–1.2 g/kg can positively influence muscle function among elderly adults.⁴ The recommendation for people exercising or playing sports professionally is 1.2–1.5 g/kg and for bodybuilding and force sports 1.7–1.8g/kg.^3,5,6 However these sources also mention that even strength-trained athletes should not exceed the protein intake of above 15 percent of daily energy consumption and for people that practice recreational sports (2–3 times a week) that intake should be around 10–12En%.^5,6

For a person that minds the daily intake, also these amounts should be reasonable to meet with a healthy nutrition pattern. Another case of increased protein need is when both private and occupational life requires physical activity. For people with a very active lifestyle, standing work, and fitness activity of more than three times a week, the protein need could be higher. However we normally see a higher total nutritional intake in those groups which equals the balance out and makes it also unneeded to consume additional protein rich products.

The Misassumptions
What is often misunderstood is the term 'sport.' In dietary practice, clients come for advice concerning protein intake, assuming the need is increased because they started to exercise more often. The suggestions they come with are: consuming protein rich products and maybe consider drinking a shake at the gym after the training. While the essence of the thought is right, the need for protein is higher, the exercise length and the need for loss of fat tissue is not considered here. In the anamneses it often comes to the front that the exercise is increased from one to 2—3 times a week of one hour per training. In terms of protein requirements this is considered as 'recreational sport' which does not require any extra intake above the 0.8— 1.0g/kg depending on the age and body condition.^1,3,5,6 The previously mentioned higher intake requirements that account for professional athletes and force sports are therefore not accountable for physical activity that is not preformed daily. It is important to understand that the increased intake guidelines are designed for people that practice sports every day for no less than two hours (professional sporters) and normally also under the supervision of a skilled nutrition specialist. Most people cannot be placed in this category and therefore should not exceed the normal recommendation. The use of protein rich (sports) products is therefore definitely not needed for most individuals that practice the so-called 'recreational sport.'

An additional fact to consider here is the initial purpose of the sport activity. In many cases clients increase their activity frequency to lose weight and/or to stay in form. In this case the increased protein need should not be considered at all. By consuming more protein without balancing your full nutrition pattern the total daily caloric intake will increase. That could result in no weight loss during exercise and in the case of using sport products even a weight gain and negative burden to the body. This is because many sport products contain apart from protein more calories than regular foods.

Misleading advice
On the Internet forums we found recommendations that vary between 1.5 and 2.8 g/kg protein intake and most of them suggest an intake of 2.0g/kg when practicing physical activity or sports. This amount is exceeding the healthy recommendations two to three times and is hard to be met without protein additives. We therefore assume that those recommendations are provided by the sport product marketing industry in order to increase the sales. However the down side of this is that these recommendations might be followed. Evidence from a review of 32 studies shows that increased protein consumption of above the recommended 0.8g/kg among healthy adults can lead to negative health effects due to high metabolic burden on kidneys, liver and bones, and increased risk for cardiovascular diseases.² But also the recommendations for professional athletes that are mentioned earlier all warn not to exceed the intake of 15En% to avoid the metabolic burden. With a 2.0g/kg intake this percentage will be exceeded. What is seen in practice is that most people have a sedentary lifestyle and practice sports no more than 2—3 times a week. Therefore their need does not exceed the recommendations for healthy people with a normal range of physical activity.

Take Home
Keep on exercising, compliment your activity with good nutrition and natural products to keep up the healthy lifestyle. Try to count your daily protein intake and keep it to the recommendations that are supported by scientific research. Consider your whole lifestyle when determining your daily needs and consult a certified nutrition coach for advice and tips in your personal case.

References:

1. I. Dalimaris. Review Article: Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults. International Scholarly Research Notice Nutrition Hindawi Publishing Corporation, 2013.
2. International Food Information Council. Protein and health factsheet 2011. http://www.foodinsight.org/Content/3840/IFIC_ProteinFactSheet_FINAL.pdf
3. The Netherlands Governmental bureau for food information 'Voedingscentrum'. Searched for: protein intake. Assessed on 11.6.2016. www.voedingscentrum.nl
4. N. E.P. Deutz, J.M. Bauer, R. Barazzoni, G. Biolo, Y. Boirie et al. Protein intake and exercise for optimal muscle function with aging: Recommendations from the ESPEN Expert Group. Elsevier Clinical Nutrition, 2014.
5. L. Burke, L. Bell, M. Cort, G. Cox, L. Faryhing, Current Conceptss in sports Nutrition. Australian Institute for Sport 2008.
6. SM Philips Protein requirements and supplementation in strength sports. Elsevier 2004.