proteine

Protein: how much is really necessary

Nutrition Basics

Protein is often mentioned, but how much does an athlete really need? Required daily protein intake remains a somewhat cloudy issue. Some argue significant quantities of protein are required for strength sports. But the same people often claim endurance athletes could (almost) do without it.  What’s the truth?

Daily protein requirement

Before looking at how much protein an athlete needs, let’s look at how much a non-athlete needs.

A healthy adult who doesn’t do any form of physical activity and who isn’t very active during the day should eat 0.8 g per kilogram of body weight per day. So, a 60kg-woman should consume 48 g and an 80kg-man, 64 g.

These quantities increase for children, growing adolescents, and pregnant or breastfeeding women.

Why is protein needed

Our bodies experience constant protein turnover. In simple terms, this is the replacement of the individual building blocks (amino acids) that make up our bodies – a process that happens almost every minute we’re alive. Protein is continually being degraded and synthesised. Clearly, such change requires the necessary “spare parts”. And since muscles are made of them, they need regular supplies. Net protein loss occurs via the skin, which flakes off constantly, nails, hair and even faeces (intestinal epithelium).

 

running

Why athletes need more protein

There are four factors why athletes need more protein than non-athletes. Let’s look at them together.

1. Athletes generally have a higher muscle mass percentage than non-athletes. So, more “building blocks” are needed to manage the turnover, even when resting.

 

2. Training causes a degradation in protein muscle structures for various reasons (mechanical, hormonal and oxidative stress), even without injury. Such losses obviously have to be replaced each time, each training session. This is why new protein needs to be made available through one’s diet, in addition to that needed when resting.

 

3. Training is basically adaptation to exercise, which amounts to the actual growth in your sporting capacity through the synthesis of new proteins. I’m mainly talking about contractile protein, thus muscle mass, which is especially important in sports where force and power are critical for success. But we mustn’t completely forget about the protein involved in energy metabolism, particularly when endurance is the keystone to achievement. In pretty much every case, new protein has to be provided through what you eat if you want to make new protein – muscle or not – that helps you boost your potential.

 

4. At times, athletes don’t only use carbohydrates and lipids , to produce energy, but also amino acids. The amount of energy from amino acids varies. It tends to be higher in less well-trained athletes and lower in those who are in better shape. The upper threshold is about 6-10% of overall energy expenditure, provided we’re talking about prolonged effort.

How much protein should an athlete consume?

Even in cases where all four of the conditions above co-exist, daily protein intake shouldn’t exceed 2g/kg. Here is a list of the upper thresholds for protein intake by athlete type:

  • Endurance events: 1.2-1.4 g/kg/day
  • Team sports and games: 1.2-1.8 g/kg/day
  • Strength events: 1.4-1.8 g/kg/day
  • Disciplines with weight divisions: 1.4-2.0 g/kg/day

Plus, remember it’s important not only to get the amount right, but also the time when you ingest protein.

 

sport-squadra

In summary: when to consume protein

To make optimal use of protein availability in one’s muscles, an athlete should avoid consuming the daily amount of protein in a single meal. There are three reasons for this.

 

1. First, protein can’t be stored by the body, so any excess protein (i.e. above what can be used more or less immediately) is degraded and eliminated by the body.

 

2. Secondly, each meal and snack needs to contribute to reaching the real daily protein requirement.

 

3. Finally, the post-training muscle adaptation and tissue repair process continues for a number of hours following training. The best way to facilitate these processes is to ingest protein during this time window in a series of portions.

 

Additionally, every main meal should have the right amount of protein and each planned snack should also contribute extra protein. The precise amounts vary from athlete to athlete and day to day, depending on the times of training sessions and meals.

 

More specifically, to achieve optimum efficacy from a strength session, you should usually consume protein once the session is finished. In those initial post-training hours, your body is ideally suited to using any protein ingested to synthesise protein. This capacity drops off after a few hours, eventually reaching zero about 24-48 hours following exercise.

 

References

  • Arcelli E. Che cos’è l’allenamento, Sperling & Kupfer Editori, Milan, 1990.
  • MacDougall JD, Tarnopolsky MA, Chesley A, Atkinson SA. Changes in muscle protein synthesis following heavy resistance exercise in humans: a pilot study. Acta Physiol Scand. 1992;146(3):403-4.
  • Phillips SM. Protein requirements and supplementation in strength sports. Nutrition. 2004;20(7-8):689-95.
  • Ziegenfuss T, Landis J. International Society of Sports Nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2008;5:17.
  • Arcelli E, Casiraghi E. L’assunzione di proteine. Scienza & Sport, pp. 90-94, num. July-September 2009.

 

Having graduated in Movement Science, she went on to earn a PhD in Physical Activity, Nutrition and Wellness. As an athlete, she can boast national and international honours in canoeing and triathlon. She lectures in Training Theory and Methodology in the Movement Science Department of Pavia University, and oversees training methodologies at the Enervit Nutrition Center (an advisory organization for nutrition, sport and wellness). She is also a FIDAL nutritional consultant on the Development Project promoted by Olympian Stefano Baldini. A member of Equipe Enervit since 2009, she was a student of Professor Enrico Arcelli.