how to fuel your workouts with a sports dietitian
  • December 9, 2022

Episode 15: Fuelling Yourself for Exercise (with Sports Dietitian Rose Maclean)

Today we have Accredited Practicing Dietitian, Sports Dietitian and Instagram guru Rose Maclean on the podcast. We will be talking […]

Today we have Accredited Practicing Dietitian, Sports Dietitian and Instagram guru Rose Maclean on the podcast. We will be talking all things exercise nutrition.



Rose consults with both recreational and elite athletes worldwide. Her main focus and passion is to help individuals with their performance by making sure they are fuelling adequately. She also works with a lot of individuals with RED-S which we will be discussing today.

She is a big foodie at heart and creates recipes for brands on the side which you can check out on her IG @dietitianrose.


Question 1: What made you want to be a dietitian? What types of clients do you work with?

Rose: In year 11 and 12 I developed a new interest in health and wellness and what I thought at the time was healthy eating. Through this I discovered dietetics as a job and thought it was perfect. After learning more I realised that the behaviours I thought were ‘healthy eating’, actually were quite disordered. I discovered sports dietetics in university and my interest was actually sparked by an assignment where we had to run 10 kilometres which I had never done before. After learning more about sports nutrition I realised myself, that when I was training for cross-country in high school I had menstrual irregularities as result of my what I thought of at time were ‘healthful’ behaviours. For instance, eating salads for lunch. And as a result, my performance was shocking. So now that I know more, I want to be able to help others who are in the same place with their performance.


Kiah: It is unfortunately so common that we see these so called ‘healthful’ behaviours get glorified on social media but a lot of the time they in fact so disordered.


Question 2: As a dietitian on social media/in the online space, what is the most common misinformation that you see about exercise nutrition?

Rose: Number one is that carbs are bad for you or unhealthy. Particularly as a sports dietitian as carbs are so important for training, especially moderate to high intensity training, to give us fuel. They also play an important role in reducing fatigue and promoting recovery as well as so many other important functions like gut health. However, they are currently so demonised, and many people think they need to be eliminated to be healthy.  

The other big one is fasted cardio for weight loss. Fat oxidation burning and fat loss are actually two very separate concepts. Just because you are training fasted, this doesn’t mean you are actually tapping into your fat stores and losing fat.


Question 3: How do you know whether you’re eating enough for exercise?

Rose: That’s a really good question. A few things you can look out for:

  • The number one thing to look out for is that you feel energised throughout the day and while training and hitting the wall or falling into a slump mid-session.
  • The second thing is feeling in control around mealtimes and not thinking about food 24/7.
  • A big one for females is ensuring you have a regular menstrual cycle. An equivalent for males is by assessing libido.
  • Another big one is seeing improvements in your performance.
  • Recovering well and not constantly getting sick or injured.

It is so individualised how many calories every person needs which is why getting individualised advice is important and we don’t recommend following an arbitrary meal plan you find on the internet.


Question 4: How do you define what is a healthy relationship with exercise and what are some signs of an unhealthy relationship with exercise?

Rose: Signs of an unhealthy relationship with exercise include:

  • Using exercise for unhealthy motivations such as to purge or to ‘earn’/’burn off’ your calories (e.g. the mentality that you have to go for a run to burn off a chocolate bar). And if you think of your total energy intake across the day, exercise only makes up 10-15% of it.
  • Managing pre-occupation with weight gain – particularly in the disordered eating space.
  • Using smart watches to judge the succession of your session on the amount of calories you have burnt. Instead, I recommend just using the performance based functions.


Kiah: While we’re on that topic, how accurate even are they?


Rose: Quite inaccurate. I read a study yesterday that Apple watches in particular can overestimate calories by up to 40%. So this is another reason not to rely on them as indictors for calories burnt.


Meg: We were also talking before recording about people feeling the compulsion to ‘close their rings’ e.g. pacing at night to try and complete it. Using exercise to complete their rings rather than for all the other benefits such as feeling fit/strong or the mental health benefits.



Question 5: You said previously you work with a few athletes with RED-S. Do you mind elaborating on this?

Rose: RED-S (or relative energy deficiency in sport) is a big umbrella term that describes low energy availability. Low energy availability is a mismatch between energy expenditure and energy intake where there isn’t enough residual energy intake leftover to fuel the basic functions of life. As a result, the body will dial down the functions it perceives as less essential such as our reproductive, endocrine and immune systems plus a range of other things. It does this to conserve enough energy for us to survive. Performance is also usually compromised as a result, for instance waking up exhausted, being more fatigued, decreased concentration and just poorer or plateaued performance in general. So, if you feel like you make have a few of these side effects happening, it may be worthwhile looking in to.


Kiah: Would you say there is one symptom that you see more commonly?


Rose: That’s a great point because everyone can present so differently. Some people may have lots of the symptoms I mentioned previously whereas some people come to me just feeling really fatigued or with an irregular/absent menstrual cycle. It is so individualised


Meg: So if in doubt, just work with a sports dietitian.


Question 6: What are the risk factors for RED-S?

Rose: To bring it back to before when we were talking about how RES-S or low energy availability is due to a mismatch between energy expenditure and energy intake is due to a mismatch. With the energy expenditure side of things:

  • It may be due to a high/moderate training load or even just a very active lifestyle/job.
  • Another risk factor is a poorly constructed training program. Especially those with minimal rest days.
  • Also exercise dependence or addiction.

On the energy intake side:

  • The major one is a lack of nutrition education or a misunderstanding of how much you actually need to be eating fir your training load.
  • Even just a lack of motivation to cook or eat.
  • Another big one is eating disorders and disordered eating. This may be in general or athletes wanting to look a certain way for their sport.


Kiah: An interesting stat I saw the other day was that 45% of female and 19% of male athletes struggle with an eating disorder



Question 7: How do you treat RED-S?

Rose: The treatment is focused on treating or reversing the underlying cause of the energy availability. We therefore increase their caloric intake to match their energy demands. This includes working with the appropriate healthcare team such as a psychologist and exercise physiologist.




Question 8: Other than nutrition, what other aspects should we be thinking about to improve performance (in the gym, in life, in different sports etc.)?

Rose: Such a good question as often because focus so much on the nutrition side of things that we forget about all the other aspects that can help.

  1. Sleep – so important for recovery, performance and general daily functioning. At least 7-9 hours if not more, some research even suggests 9-11 hours for athletes.
  2. Rest – many people neglect rest days even though it is one of the most productive things you can do long term.
  3. Hydration – evidence shows that 2% or greater fluid deprivation can impact performance. Look for pale yellow urine (see the urine chart attached). 30-35mL fluid per kg body weight is a good general guide but will vary depending on your sweat rate with exercise.
  4. Supplements (this is like the sprinkle on top of our other fundamental aspects) – there are some evidence-based ones I recommend as well as some not so beneficial ones (for instance, fat burners are not something we should be looking to include). Caffeine, creatine, beta alanine are a few that I often recommend but these are just performance enhancers and don’t replace adequate nutrition.
    • Caffeine – reduces the perceived effort of exercise so it makes it seem easier. Guidelines recommend 1-3mg caffeine per kg body weight taken before exercise. However, if caffeine gives you anxiety then I recommend avoiding it and focusing on pre-training carbs instead.
    • Creatine – helps with increasing muscle mass as well as cognition and general performance.
    • Beta alanine


Kiah: One thing I often see come up is people using pre-workout and BCAAs all the time. What is the current research around that?


Rose: Supplementing BCAAs (branched chain amino acids) on top of adequate protein is unnecessary. Pre-workout is quite a nuanced topic. I personally don’t recommend it to my clients and instead prefer to focus on the caffeine aspect which we can get in other ways such as coffee. A big issue with pre-workout is that they aren’t regulated and can contain banned substances. For the general population, this isn’t too big of a risk. However, for elite athletes it is crucial they only consume products that have been tested for banned products as to not get done for doping.  


Question 9: What are your favourite pre-workout snacks?

Rose: I love this question. It depends on the person’s unique requirements as well as exercise duration and type. But, as a general guide for moderate to high intensity workouts, 30-60 minutes prior to exercise we want easily digestible carbs. Also low in fat and fibre as these take longest to be digested and can cause some discomfort.

  • Fruit or fruit juice
  • Crumpets or rice cakes with honey or banana and honey
  • Low fibre cereal like Coco Pops, Corn Flakes
  • Dates

Often these foods are demonised for being too processed or high sugar. But, context is important. Performance carbs are going to be very different to your general nutrition carbs. So, for a majority of they day we want more of our wholegrain carb choices but for performance we want the quicker acting options.



Finally, where can we find you?

  • Instagram: @dietitianrose – I am a massive foodie and love to cook so you can find lots of recipes


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