Sports Nutrition: Myth or Fact?

If you want to reach your full athletic potential, you need to take your nutrition as seriously as you take your training. There is a lot of conflicting nutrition information out there, so let's get to the bottom of the most common sports nutrition myths and facts.


You can’t out-train a bad diet. If you want to reach your full athletic potential, you need to take your nutrition as seriously as you take your training. Thankfully, this does not mean eating kale salads for every meal! There is a lot of conflicting nutrition information out there, and as a Registered Sports Dietitian, it is my job to provide you with evidence-based nutrition recommendations that will help you excel as an athlete. Below are some of the most common nutrition myths and facts I hear from athletes, so hopefully this will help clear up some confusion!

Before reading the answers to the following statements, try to think whether you think they are true or false.

1. Protein consumption is so important because amino acids are the preferred fuel source for muscles

Myth. And if you got this one wrong, that’s OK because most athletes do! Protein is NOT our muscles’ preferred fuel source. Carbohydrates are actually the preferred fuel source for your muscles (and brain!). During short, high intensity bouts of exercise (for example, sprints), carbohydrates are the only energy source that can fuel your body quickly enough. In fact, during the first few minutes of exercise, carbohydrates almost exclusively meet your energy demands. Your ability to keep a high level of intensity throughout your entire workout largely relies on your body’s carbohydrate stores. But you might be wondering, what about fat? Isn’t fat used as an energy source? Well the long and short of it is that carbohydrates are needed in order to metabolize fat, and this process also takes longer. So when you’re needing to do high intensity exercise, fat is not an efficient fuel source. So remember, fuel = energy = carbohydrates = your muscles’ preferred fuel source!

2. Post-workout nutrition is actually more important than pre-workout nutrition.

Myth. They’re equally important! Just like how breakfast is not actually the most important meal of the day. Breakfast is definitely important to fuel your body for the day ahead, but it’s just as important as lunch or dinner. Similarly, pre workout nutrition is essential to keep your body fuelled for your workout. If you aren’t adequately fuelled, your performance suffers, and therefore your post workout nutrition is inadvertently less effective as well.

3. Whey protein seems to be superior to other tested proteins in regards to muscle synthesis and repair

Fact. After resistance and strength training, protein and carbohydrate consumption is recommended to facilitate muscle synthesis and repair, and replete glycogen stores. Studies have shown positive increases in muscle protein synthesis when high-quality proteins were consumed after exercise (ex. Milk, eggs, lean red meat). However, a superior increase in muscle synthesis has been reported after consumption of whey protein when compared to other tested proteins. Researchers believe this is largely due to the leucine (type of branched-chain amino acid) content of fluid-based dairy foods. Additionally in some studies, branched-chain amino acids seem to have superior digestive and absorptive properties. Whey protein comes from cow’s milk, which is 20% whey protein and 80% casein protein. This means that you could drink cow’s milk and get the same benefits regarding muscle synthesis and repair, however whey supplements are often preferred because it is a more concentrated source. For example, there are 8 grams of protein per cup of milk. But since milk is only 20% whey protein, you’re getting 1.6 grams of whey and 6.4 grams of casein per cup (i.e. not the recommended ~15-25 g of protein post-exercise). That being said, casein is still considered a high quality protein so if you are looking for an alternative to whey supplements, milk is still a good choice!

Long story short, whey protein supplements are not essential because consuming high quality proteins (milk, egg, lean red meats) after resistance exercise are beneficial for muscle synthesis and repair. However, you may experience greater muscle synthesis using whey protein.

4. You need to replace the fluid lost in sweat by up to 150%

Fact. To ensure your body is adequately rehydrated, you need to drink 1.0 – 1.5 L water per kilogram of body weight lost after exercise. Athletes should aim to fully restore fluid losses in between exercise sessions. Remember, being dehydrated by only ~2% can have negative effects on your performance – so stay hydrated!

5. Registered Dietitians and Registered Holistic Nutritionists are the same

Myth. I like to include this myth to assure all athletes that they are getting evidence-based, accurate nutrition information. In British Columbia, “nutritionist” is not a regulated health profession nor is it a protected title. This means that nutritionists are not subject to any regulatory or government oversight, unlike dietitians. No specific qualifications are needed to be a nutritionist, so anyone with an interest in nutrition can use it. Across Canada the title “dietitian’ is protected by law, just like physician, pharmacist, or nurse. Dietitians need to be registered with a regulatory body, such as the College of Dietitians of British Columbia. Additionally, because it’s a regulated health profession, many extended health care plans also cover the services of a dietitian. In B.C., dietitians must have a five-year university degree in nutrition with at least 1250 hours of supervised, hands-on training, pass a national competence examination and undergo regular criminal record checks. Sports dietitians have combined knowledge in several topics, including clinical nutrition, nutrition science, exercise physiology, and application of evidence-based research, in addition to being passionate about sports! To read more, please read the Vancouver Sun article found here.

6. Cramps are caused by not eating enough potassium

Myth. What we know about cramps is that the main risk factors include premature muscle fatigue, previous occurrence of cramps during exercise, increased exercise intensity and duration, and inadequate conditioning. Nutritionally, inadequate glycogen stores (not enough carbohydrate) and/or low energy availability may contribute to fatigue, and therefore cramping. So how do we prevent cramps? Evidence suggests that cramping results from muscle fatigue, so adequate training/conditioning, rest, and stretching appear to be the best ways to prevent cramps. Nutritionally, ensuring you are adequately fuelled and hydrated will help prevent fatigue, and subsequently may prevent cramping as well.

7. Vegetarian athletes can perform equally as well as non-vegetarian athletes, even when consuming plant-based protein.

Fact. A well-planned and well-balanced vegetarian diet can support athletic performance equally as well as a non-vegetarian diet. Some good plant-based proteins include soy (tofu, edamame, tempeh), quinoa, nuts, seeds, and legumes. In fact, vegetarian proteins have excellent health benefits due to their low fat (specifically saturated fat) and high fibre content. Lacto-ovo vegetarians also have the option of dairy products and eggs, which are also high quality protein sources. If you are a vegetarian athlete or thinking of becoming vegetarian and you want some help optimizing your diet, feel free to contact me to book an individual counselling session (

8. Supplements are beneficial for everyone, and can make you stronger and faster.

Myth. When possible, I always recommend food first over supplements. However, there are some cases where supplements are beneficial. Nutritional supplements are necessary when someone is unable to get enough nutrition through food, or when the body is unable to adequately absorb nutrients from food. Some examples are iron supplements, vitamin D supplements, calcium supplements and high protein/high calorie supplements (Boost, Ensure). Other supplements include performance-enhancing supplements. Out of the hundreds of available performance-enhancing supplements, there is only evidence supporting a handful of them. Some of the supplements out there may actually do more harm than good. If you have questions about supplements you are taking, feel free to contact me at

By Stephanie Dang, BSc, Registered Dietitian.


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