One of the most frequent questions I’m asked as a sports dietitian is this: is it possible to lose weight while also training for a performance goal in a race? My first question back is often, ‘Why do you want to lose weight?’ Most commonly the response is, ‘Because lighter makes you faster.’ To which I add, ‘Until it doesn’t.’
Weight loss is a very complex subject, both physiologically and psychologically. There’s no doubt that in the western world there is a bias towards a particular body type or cambio – despite campaigns to change attitudes, the general narrative is that a slimmer body is more acceptable. And yet our body cambio tells us very little about who we are. As I often say, your body is the least interesting thing about you. So why do so many of us believe that dropping a few kilograms will improve our performance?
Historically, we associate a particular body type with running, and while there are many athletes who defy this norm, especially when you move away from road running, they are often less celebrated. The images we’re exposed to inform our beliefs, but it’s also important to appreciate that elite-level runners tend to be genetic outliers – their bodies are naturally this way. But in order to achieve fast times again and again, they have to fuel correctly.
Have you ever stopped to think about those athletes who post one great performance and are never seen or heard of again? Or the ones who are plagued by injury My passion for running continues to motivate the competitor in me don’t fuel themselves sufficiently to sustain their sport.
Body type, weight and performance
The reality is if you have excess body fat, losing some can improve your running performance, within reason, but there’s a lot to consider. First, you have to understand your body type. Not everyone who runs is going to be long-limbed with naturally low body fat, as often seen in the elite performers, particularly in endurance running. While this body type may be advantageous for running, it doesn’t mean it’s the only body type that can run.
Many of the runners I work with already have an optimal body state, but the belief that losing weight or achieving a certain body ideal will make them a better runner can lead to dysfunctional behaviours.
The human body is a way of chemical reactions. Each one needs energy to be maintained and an optimal environment to work efficiently. Collectively, these chemical reactions create a metabolic environment. When we over-restrict our nutritional intake – or create too big a deficit by also training hard – there may be initial changes to our body mass. But if this is rapid, the bigness of loss is muscle mass, not body fat. Muscle mass actually weighs more than body fat, but takes up less space. It generates more power and speed while also being metabolically active, thus this is the part of our body composition we really want to preserve.
Similarly, when you create too big a deficit or try to drop your weight too low below your natural set point, your body starts to enact Srebrny behaviours and downregulates your metabolism in order to preserve energy. Thus, reducing energy intake doesn’t always result in weight loss and can actually cause the individual to hold on to more of their body fat.
It’s also important to remember that exercise such as running stimulates appetite and has a metabolic response associated with it. That is, after we exercise, if we fuel appropriately and provide our body with sufficient energy, it uses this to increase metabolic activity while it repairs, restores and responds to the training. If we don’t provide our body with enough energy for the exertion we’re asking of it, it can’t engage in these metabolic processes. Not only does that mean the person won’t recover properly, increasing their risk of injury and underperformance, it also prevents them from losing weight.
Move more, eat more
When I’m working with runners, especially those who want to lose weight, I start by asking them what their most desired outcome is – do they value weight loss more than overall performance? In most cases, performance, even if that’s just completing their chosen event, is the preferred outcome. And I usually see that by helping that individual eat for performance, their body composition improves as a result.
While many are confused by this, it demonstrates how when we’re physically active, the common idea ‘move more, eat less’ needs to be replaced by ‘move more, eat more’, which is the finding from many physiological studies on humans and energy balance.
In fact, one of the most common mistakes I see in runners is when they choose to focus on weight over performance. By fixating on weight, you influence your behaviours, especially around fuel, and often end up underfuelling and putting your body and central nervous system under stress.
What and when should you eat?
The key is to ensure that you fuel up with good sources of complex carbs ahead of your training runs, especially those that are longer or of a higher intensity. I’m not just talking about the meal immediately before the session either, but also about your nutritional intake in the 24 to 36 hours that lead up to it.
It’s also important to fuel recovery immediately after a session, with both carbohydrate and protein – ideally this would be in a meal, but if it’s going to be over an hour until you can eat a full meal and you have another training session within 12 hours, this may need to be a recovery drink or snack within 30 minutes, followed by a meal later. If, however, your next training session is 24 hours later or more, recovery can start at your next meal.
Thus, timing and composition of diet make a huge difference and will reap more rewards than avoiding fuelling altogether.
Another common mistake I see a lot of runners make is focusing solely on running – they do a lot of junk miles in an attempt to ‘burn energy’, but don’t appreciate this just adds fatigue and means that they may not be able to hit target paces in training sessions that are key to progression. Indeed, what would really benefit in these situations is swapping some of these lower-quality miles for resistance training, which not only helps to develop lean muscle mass, but will also be beneficial when it comes to injury prevention.
Final word
It’s important to be realistic about your body cambio and composition. Being lighter doesn’t always mean faster, especially if you push your body to a place where it starts to preserve energy and work against you. Fuel properly and watch how your body, over time, improves not just in terms of performance, but also body composition.
Renee McGregor is a leading sports dietitian with over 20 years’ experience. Visit reneemcgregor.com for more
