The main mistakes in pre/post-workout nutrition

By Gonçalo Matias Santos

Nutricionist (6007N)

A common concern for those who start training is knowing what to eat before and after training. Although it's difficult to make specific recommendations without taking into account the goal, sport, frequency and intensity of training, it is possible to give some general guidelines for those looking to improve their performance (Thomas et al., 2016).

Firstly, it's important to understand how our body obtains energy to carry out movements in high-intensity activities. Muscle carbohydrate reserves, or muscle glycogen, are fundamental for energy production in this context (“Nutrition and Athletic Performance,” 2016). Fat, on the other hand, is a less important source of energy for intense activities due to the longer process involved in consuming oxygen.

However, the meal or snack before training (up to 2-3 hours before) won't have much impact on filling muscle glycogen reserves, as these take between 4 and 6 hours to be replenished (Burke & Hawley, 2018). In other words, if someone trains at 6pm, a full lunch around 1pm (with rice, pasta, potatoes, bread, etc.) will have more of an impact on replenishing these reserves than a meal shortly before.

In addition, it's important to know that the use of muscle glycogen depends exclusively on the muscles we're working. In other words, if you train your lower body on Monday, for example, you can train your upper body the next day without worrying about immediately restoring these reserves. The most important thing is to ensure adequate daily carbohydrate intake, which for regular bodybuilders is between 3 and 5 grams per kilogram of body weight (Kerksick et al., 2017).

With this in mind, you're probably wondering: ‘So, what's the point of a pre-workout meal?’.

When we talk about the pre-workout meal or snack (30-60 minutes before), the intake has two main objectives:

• Provide glucose (‘sugar’) to the blood in order to avoid feeling hungry during training (Thomas et al., 2016).

• ‘Saving’ glycogen reserves, especially those in the liver, to avoid feeling tired or weak during training (this can differ greatly from person to person) (Kerksick et al., 2017).

A third reason to consume carbohydrates before training is that it can help prevent an increase in the inflammatory response - a factor that impairs iron absorption. In people at risk of iron deficiency, this inflammation can contribute to aggravating or precipitating anaemia, which makes carbohydrate intake an important measure for general health (Thomas et al., 2016), especially for those most at risk of being affected by this deficiency, such as women with significant iron losses due to menstruation, runners with iron losses due to impact (haemolysis), people who follow a vegetarian diet or who have absorption difficulties for medical or medication reasons.

In terms of food options, it is recommended that the pre-workout meal contains carbohydrates with a low fibre content, to ensure a quick release of glucose into the blood and avoid possible intestinal discomfort (“Nutrition and Athletic Performance,” 2016). Some options that work well are: a sachet of fruit puree, a banana, 3-4 rice/maize tortillas, dehydrated fruit (such as 2 dates), among others. However, if the person feels fine training without consuming anything before training, and still performs well, in general it's fine to follow this approach.

Regarding protein before training, it's not mandatory. If it is included, it should preferably be quickly digestible (a whey shake with fruit, for example), and you should give yourself an ‘intestinal safety’ margin of at least 60 minutes before training. Sources rich in fat, such as meat, fish, eggs and dairy products, may not be the most suitable in this context (Kerksick et al., 2017).

When it comes to post-workout carbohydrate intake, it's important to realise that in a 60-90 minute bodybuilding workout, muscle glycogen reserves are not significantly depleted to the point where aggressive replacement is necessary. This type of replacement is only relevant for those who train more than once a day and repeat the same muscle groups - a situation that doesn't apply to 99.9% of people (Burke & Hawley, 2018).

In fact, protein has a priority function post-workout, as it helps with muscle recovery and protein synthesis. The sources I mentioned earlier (such as meat, fish, eggs and dairy products) are perfectly suitable for this purpose. There is no advantage in opting for protein shakes, apart from convenience. As for timing, the ideal is not to remain in a ‘protein fast’ for more than five hours - in other words, without consuming foods containing protein - after the last meal containing protein. A traditional meal, such as lunch or dinner, with 20 to 40g of protein, is more than enough to serve as a post-workout meal. In this context, the amount of fibre and fat is not a concern (Kerksick et al., 2017).

I hope I've helped to clarify the main issues I get asked about pre/post-workout nutrition. If you want to improve your performance through a diet and, if necessary, supplementation that suits you, you can always get in touch to schedule your nutrition appointment.

Bibliography

Burke, L. M., & Hawley, J. A. (2018). Swifter, higher, stronger: What’s on the menu? Science, 362(6416), 781–787. https://doi.org/10.1126/SCIENCE.AAU2093

Kerksick, C. M., Arent, S., Schoenfeld, B. J., Stout, J. R., Campbell, B., Wilborn, C. D., Taylor, L., Kalman, D., Smith-Ryan, A. E., Kreider, R. B., Willoughby, D., Arciero, P. J., VanDusseldorp, T. A., Ormsbee, M. J., Wildman, R., Greenwood, M., Ziegenfuss, T. N., Aragon, A. A., & Antonio, J. (2017). International society of sports nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition, 14(1). https://doi.org/10.1186/S12970-017-0189-4

Nutrition and Athletic Performance. (2016). Medicine and Science in Sports and Exercise, 48(3), 543–568. https://doi.org/10.1249/MSS.0000000000000852

Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics, 116(3), 501–528. https://doi.org/10.1016/J.JAND.2015.12.006