Mythbusters: the Nutrition Edition
Hello everyone! Gyms are opening again, but with the excitement about fitness ramping up, the bro-science tends to get kicked up a notch as well. Specifically, nutrition bro-science. While this will not be a biochemistry or physiology lesson, I hope you find this informative. ☺ (Disclaimer: I am NOT a dietitian; if you are looking for specific nutrition advice, I recommend consulting with one!).
1. “As an active person, I must eat 800g of protein a day, and chug a protein shake within 10 seconds of my workout ending.”
TL;DR: No. 1.2-2.0g/kg of protein a day is sufficient. Meeting your total daily protein requirement with consistent meals is the most important.
First, protein requirements. The American College of Sports Medicine and the Dietitians of Canada recommends 1.2-2.0 g of protein per kilogram of bodyweight as the amount necessary to support repair, protein turnover, etc1. Example: if you are 50kg, you will need about 60-100g. Where you would fall on this “range” depends on a few things, but energy availability is the most important factor; if you are not eating enough calories (especially from carbohydrates), protein will be used for energy rather than muscle repair, growth, etc¹. All this applies to both strength and endurance athletes; evidence suggests that adequate protein intake supports recovery from endurance exercise and promotes endurance-related adaptations². (i.e., helps you recover faster and contributes to increased endurance!)
Here is a visual guide on protein amounts in foods: . One serving of meat/fish is ~25g protein, one serving of beans/legumes is ~10g protein.
Second, the “anabolic window”. In terms of muscle growth, there isn’t solid evidence that having a cow’s worth of protein RIGHT after your workout is of utmost importance – in fact, there is debate on its existence³. There is more evidence, however, that consistent protein intake throughout the day is more beneficial. For example, Areta et. al demonstrated that intermediate “doses” of protein (20g every 3 hours) elicit greater rates of muscle protein synthesis, compared to larger but less frequent “doses”, or very small “doses”⁴. As such, the International Society of Sports Medicine recommends that the primary focus for active individuals should be meeting daily protein requirements with consistent meals (i.e., every 3h)⁵.
2. “In order to be fit and a real athlete, I have to eat clean or do [insert diet name].”
TL;DR: No. As an athlete, the requirements your diet should meet are: sufficient calories and adequate amounts of each macronutrient. This is difficult to do with most mainstream diets, which are often restrictive in nature.
Some of this is a little bit informal, but bear with me. First, let’s define “clean eating”. Here’s where the first problem lies – there is no formal consensus on the definition of “clean eating”. Additionally, “clean” foods may vary. For example, some people consider wheat flours “clean”, while others consider them far too processed (you can Google it!). Common buzzwords between various definitions include “natural”, “unprocessed/minimally processed”, “unrefined” - but you also hear “avoid”, “minimize”, “skip”. So, it often leads to more restrictive eating habits which, as performance athletes, we want to avoid. As athletes, we are more likely to be under-fueling, and it is a concern – a recent review reported that 22%-58% of athletes have low energy availability (i.e., are undereating)⁶. “Relative energy deficiency in sport” (RED-S) refers to impaired athletic performance and other negative physical/psychological effects that occur due to insufficient energy intake7. Not only is athletic performance negatively affected, but so is muscle protein synthesis making muscle injuries more likely), immune function, bone density (which can lead to stress fractures, which from personal experience, are 0 fun), among other effects⁷.
I spoke about clean eating, but these issues are also common in some other “diets”, especially the tendency for those dieting to become restrictive. On a related note, research suggests that intermittent fasting appears to be detrimental to athletic performance (particularly endurance-based sport); at best, it has no effect⁸⁻⁹.
With all this said, the optimal “diet” for athletic performance and fitness is balanced, and gives you enough energy to perform and recover from workouts. Here are some visual guides developed by sport dietitians (The Athlete's Plate®) which show you what your meals as an athlete should look like (here, the “moderate” training plate should be your baseline).
Here are a list of IG science-based nutrition accounts that I recommend checking out:
@eatwell.runbetter (tailored to running, but she gives good general nutrition advice - she’s a dietitian!)
On a final note (repeating myself again): if you feel lost with nutrition or would like personalized recommendations, I strongly suggest consulting with a dietitian. U of T has dietitians in their Health and Wellness Centre.
References
1. Thomas, D. T., Erdman, K. A. & Burke, L. M. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J. Acad. Nutr. Diet. 116, 501–528 (2016).
2. R., M., M., C., L., A. & A., H. Beyond muscle hypertrophy: why dietary protein is important for endurance athletes1. https://doi-org.myaccess.library.utoronto.ca/10.1139/apnm-2013-0591 39, 987–997 (2014).
3. Aragon, A. A. & Schoenfeld, B. J. Nutrient timing revisited: is there a post-exercise anabolic window? J. Int. Soc. Sports Nutr. 10, 5 (2013).
4. Areta, J. L. et al. Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. J. Physiol. 591, 2319 (2013).
5. Kerksick, C. M. et al. International society of sports nutrition position stand: nutrient timing. J. Int. Soc. Sports Nutr. 14, (2017).
6. Logue, D. M. et al. Low Energy Availability in Athletes 2020: An Updated Narrative Review of Prevalence, Risk, Within-Day Energy Balance, Knowledge, and Impact on Sports Performance. Nutrients 12, (2020).
7. Mountjoy, M. et al. The IOC consensus statement: beyond the Female Athlete Triad—Relative Energy Deficiency in Sport (RED-S). Br. J. Sports Med. 48, 491–497 (2014).
8. TP, A., RW, D. & BP, C. Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: A systematic review and meta-analysis. Scand. J. Med. Sci. Sports 28, 1476–1493 (2018).
9. Levy, E. & Chu, T. Intermittent fasting and its effects on athletic performance: A review. Curr. Sports Med. Rep. 18, 266–269 (2019).