Performance and clinical dietitian Renee McGregor loves her role. She spends her time advising athletes on how best to eat for peak performance, and how to keep their body working efficiently and effectively. Her skill lies in showing people what to eat but also how much to eat, and when. Although firmly based in science and cutting-edge research into nutrition, her work remains accessible and simple to understand. Whatever sports you might be into, there’s a path to optimum nutrition for you using Renee’s training and ideas. Notably, Renee has been working for the GB Paralympic team in preparation for Rio 2016, for the Olympic rhythmic gymnast team for 2012, and members of the British swimming team, among others. She is a regular contributor to health and fitness publications such as BBC Food, Triathlon 220 and Outdoor Fitness. Her three books are staples for those trying to work out what to eat when exercising – her book Training Food has been extremely well received and has been a category bestseller.
We were thrilled that Renee agreed to talk to us about her knowledge on optimum nutrition for the body. We put her in the hot seat and asked our top questions!
How does fuelling the body correctly have an impact on performance?
Putting the right fuel into the body has a huge impact on how we perform, particularly if you are trying to train or compete at high intensity. In order for our muscles to work at that rate, they need a quick supply of energy. This is only possible if we have carbohydrate available (either in the form of glycogen stored within our muscles) or through what we eat immediately before and during the exercise. If you don’t have sufficient carbohydrate available, the body will use fat stores as energy and work at a much slower rate.
Do different sports need different fuel? Why?
In a word, yes! This will be based on what energy systems are going to be used; what the body composition needs are of the sport and the duration of the sport or event. For example, fuelling for football is very different from fuelling for gymnastics.
What kinds of factors influence how much to eat before training?
What you choose to eat prior to training depends on the type of training; if this is going to be a recovery session, then you don’t need to focus on having a large carbohydrate heavy meal prior. However if the training is high intensity such as intervals on the bike or running track, then you are going to need to ensure suitable fuel leading up to this session.
Additionally, you need to think about tolerance – some people can eat within 30 minutes and still train; while others will need to ensure at least a two hour gap.
How big a role does hydration play?
Hydration is really important, particularly if you are training in warm climates or indoors where your fluid and sweat losses are much higher. Just being 2% dehydrated can have a huge impact on performance and concentration. Sports that have an element of decision-making and/or are skill based such as fencing, football or archery also need to be aware on the affects of dehydration.
Do you recommend adding supplements to diet?
I’m generally a “food first” practitioner as I think that most nutrients can be obtained through a good diet. That said there are a few exceptions. One of these is Vitamin D, which is very difficult to obtain from diet and is extremely important for immune function and muscular recovery. Another would be probiotics, which again have been shown to boost immune function in athletes. Personally, I have to be very aware of recommending supplements because of doping in high level sport; most recreational athletes don’t have quite the same concerns!
Is it a myth that different people metabolize food differently?
Different foods are metabolized by different pathways; i.e. it takes more energy to break down protein and fat, in comparison to carbohydrate. With regards to how individuals metabolize food: generally speaking, the same principles apply within each body. However, if you have a higher composition of lean muscle mass, this is active tissue and so utilizes more energy at rest. Fat is non-active. So individuals who have a higher percentage of lean muscle mass will have a higher metabolism and thus higher energy requirements than those who don’t.
What’s one of your favourite post-exercise meals?
I tend to do a lot of my training in the morning and so my favourite meal to recover with is sourdough toast with scrambled eggs and tomato chutney. It’s a great combination of carbohydrates and protein to help refuel my muscles; the tomato chutney also contains lycopene which is an antioxidant important for health.
What factors can cause stomach problems during exercise and what strategies can we use to try and avoid them?
The biggest problem is dehydration. During exercise it would cause your stomach contents to become concentrated. Blood flow is directed to our muscles rather than our stomach for digestion, thus causing its contents to become further concentrated. The body finds this difficult to tolerate and this can lead to gastro-intestinal distress.
Another cause is when individuals do not practice with the correct fuelling during training; their body under-prioritizes the ability to utilize carbohydrate. Thus when they try to use carbohydrate in a race situation, the body finds it difficult to tolerate and this can result in stomach distress.
Stomach distress can be caused by a very high fibre intake prior to training. Additionally, in female athletes, stomach distress can be caused at certain times of the menstrual cycle due to hormonal changes.
In order to help alleviate these issues it is best to work with a sports dietitian so that they can determine what is the actual cause of the distress and then advise accordingly.