Protein after resistance exercise

Do you need to take in extra protein after a strength exercise session and, if so, how much?
Scientists are still debating this question. It is an important one, even for endurance athletes, as we all need strength to practise our sport properly and to perform well. In the May edition of Sports Medicine, Stuart Philips from McMaster University has summarised what we know about this question.

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Muscle proteins are in a constant turnover: some are broken down, and other are synthesised. As long as you making more muscle proteins than you are breaking down, your muscles will grow (hypertrophy) and you will get stronger, your performances will become better and, crucially for endurance sports, you will be able to maintain good form for longer and therefore reduce your risk of injury.

Resistance exercise will stimulate muscle protein synthesis for at least 24 to 48 hours. Proteins are made of amino acids, and having more amino acids in your blood will further enhance muscle protein synthesis. After a meal you tend therefore to make more proteins than you break down. The effects of eating and exercising reinforce each other, and this is why it is beneficial to have a protein rich drink or meal after your strength training session.

However, as exercise stimulates muscle synthesis for at least 24 hours, researchers such as Brad Schoenfeld and Alan Aragon believe that timing your meals is much less important than having enough protein in each of them. They think that supplements immediately after training are unnecessary as long as you are having a healthy diet containing enough protein. I have blogged about their opinions before.

There are 20 different amino acids, but our bodies can synthesise only 10 of them. The others are called the essential amino acids, as we have to get them from food. Unfortunately, we can only synthesise muscle proteins if all the essential amino acids are available, which means that we need a well balanced diet. One of them, leucine, is particularly important, as it triggers the synthesis. Foods that contain plenty of leucine, such as whey, are therefore more effective than others to build up muscles.

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How much?

Having too much protein in your food does not help. The maximal effective amount is 0.25g protein/Kg body mass in younger people. Ageing and inactivity makes it harder to get the process of muscle synthesis started, and it is likely that we need more leucine and protein in our food as we get older. Older people may need up to 40g protein/ Kg body weight.

The rate at which the amount of amino acids rise in your blood is also important: a low level or an almost continuous delivery is much less effective than a bolus every three hours or so, as you would get from meals and snacks during a normal day.

Other components

– As yet, there is no evidence that other amino acids such glutamine or arginine, help to build up muscle.

– Carbohydrates are important to replenish your glycogen stores, but there are no reasons to believe that they influence muscle synthesis, as long as you have enough protein in your food.

In practice

Try to have at least three well balanced meals and/or snacks a day, each of which should contain sufficient protein, and schedule your workouts so that you finish before a meal. Do not eat too much protein either, as this is probably just wasteful.

As you get older, you will need more protein, especially more leucine. You will find a list of foods containing leucine by clicking here.

Never give up exercising, as inactivity and ageing are a bad combination for your muscles.

Disclaimer: this article is for general information only, and does not replace medical advice. It cannot be used to diagnose or guide treatment. If you have any concerns or questions, you should talk to a qualified health provider.

References

SM  Philips. A brief review of critical processes in exercise-induced muscular hypertrophy. Sports Med. 2014; 44 (1): 71-77.

BJ Schoenfeld,  A A Aragon and J W Krieger. The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. J Int Soc Sports Nutr. 2013; 10 (1): 53.