Weight Management for Endurance Athletes Dr Andy kirkland


I originally wrote this blog a few years ago because I knew a few athletes who were really struggling with weight management at the time, and I was dissatisfied with the advice their coaches had given them. The topic came up again last week, so I've done a wee update.

In this Blog, I’ll discuss why weight management is so important within a sporting context, highlighting some of the issues that coaches and athletes should be aware of specifically related to eating disorders.

Images are simply to look pretty rather than to relate to the text for obvious reasons. I used the words weight and mass interchangeably for ease of understanding.

Weight and Endurance Performance

In endurance sport there are two ways to go faster:

  1. To become fitter and more efficient
  2. To be lighter.

The former comes down to training effectively and consistently. Of course, individual genetics play a major role in how people respond or not to training. However, sooner or later the physiological 'limit' of human adaptation will be reached and improving performance becomes more of a challenge.

The next time you're at a triathlon or a mass participation race, observe how everyone looks. If you grouped people based on body mass, the fast group would look extremely lean and light, the middle-groupers would look average and the slow group may be carrying a wee bit too much weight (whether due to height, muscle, excess body fat or a combination of each). Of course, there are exceptions to the rule but I think these generalisations are fair. Mass affects us in different ways depending on the discipline:


The relationship between body mass and swimming performance is complex and has a lot to do with centre-of-buoyancy i.e. how mass is distributed around the body. A bit of body fat is desirable to provide adequate insulation and help with buoyancy. Performance suffers if an athlete is ultra-lean.


Cycling is also very complex in terms of body mass. On relatively flat courses the absolute power of a cyclist, regardless of body mass, is a major predictor of performance. That’s why Fabian Cancellara is so fast. His large muscle mass and long levers help him deliver exceptional power. However, it’s very unlikely that he’ll win an alpine stage of the Tour de France. That’s because as gradient increases, power relative to body mass i.e. power to weight ratio becomes more important. Lighter riders have a definite advantage when it comes to hill climbing. One reason Bradley Wiggins sited for not wanting to focus on the Tour de France again was the hard work and extreme discipline to maintain the physique that will get him over the high mountains with the leaders.


Athletes and coaches clearly understand the relationship between performance and weight. As a rule-of-thumb in running, a drop of 1kg of body mass will typically translate into a time saving of 6 seconds per kilometre. Extending that further, a drop of 3kg over a 10km run could translate to a 3-minute time saving. At elite level, that is massive!

The Tipping Point

Of course, it's not simply a case of losing weight to go faster. For all athletes, maintaining an energy balance is vital during training and for normal life. That means putting in the same number of calories as expended. The body can cope with a slight negative energy balance but drastic calorie reduction can have serious consequences.

Trying to lose weight too quickly is never good as the body may go into starvation mode, performance will suffer and in fact weight may not drop. Of course, there are examples of athletes dropping weight very quickly but they are typically supported by expert nutritionists. Such weight reduction programmes must not be used for prolonged periods of time.

There also comes a tipping point where an athlete will not be able to maintain healthy bodily function. Muscle proteins break down, infections become more common and performance suffers. In more serious cases, bone structure may weaken and osteoporosis results. For female athletes, there can be further complications relating to the Female Athlete Triad.

From a performance perspective, finding that red line of optimal body mass is the goal. That is the point where mass as low as it can be without there being any health, performance or psychological implications. For top athletes, they may push the boundary for a one-off race but they will up their weight immediately afterwards so immune function does not suffer. There is absolutely no reason for an amateur athlete to go to such extremes though.

The Psychological Side

Losing weight feels good much in the same way as getting faster feels good. Winning feels even better, not that I’ve got much personal experience of that. The triple pleasure whammy of losing weight, being faster and winning can be more addictive than crack cocaine.

"I'm getting faster as I get lighter, so if I get lighter still, I will be even faster".

In many sports, the media and society in general sees being thin, especially for females, as positive too. It's not just about performance. Exercise releases feel good hormones too and we all tend to continue to do things that feel good. Added to that, good athletes have the ability to be very disciplined, to push personal boundaries and have an excellent work ethic, and that includes managing their diet. That all sounds positive, but losing weight and training can become addictive, sometimes getting to the stage where people are unable to take rationale decisions or keep control their own weight.

A Very Complex Organ

Eating Disorders

The sad reality is that there are too many instances, especially with female athletes, where weight becomes the be-all-and-end-all, with eating disorders such as anorexia and bulimia being the result. Chrissie Wellington is a very high profile example of an athlete who has had an eating disorder. I personally know a number of women who have been successful at world level that have developed very serious eating disorders too. The fact is that most endurance athletes (see DiaGioacchino et al. 2002 as an example) want to be thinner. With an ‘elite’ mind-set the likelihood of that developing into something more serious is very high. It's worth having a read of my wee friend Nina McArthur's blog on her eating disorder. One quote stands out for me here:

They emphasised how important it was to be ‘optimum race weight’ and always to maintain a low fat diet.

Many athletes with eating disorders are very articulate, intelligent and high achievers. Some scientists argue that there are predisposing factors that make eating orders more likely. For example, neurologists have identified a correlation between these types of eating disorders and the way the brain is wired, specifically in the insula. I wouldn’t be too surprised if there was a correlation between neurology and the likelihood of elite success in sport too.

When I’m on a long bike ride, I’m rubbish at eating and the result is that for the final few hours I’m thinking about food.... milkshakes, cheese and onion pies, crisps and cake; images follow me in a giant hunger-pang thought bubble. In short, I feel ravenous! One suggestion is that people with a predisposition for anorexia feel much less hungry and are able to easily restrict calorie intake as a result.

Similarly, geneticists have identified an association between the risk of developing certain eating disorders and specific genes. Such neurological and genetic evidence is useful as it helps illustrate that athletes with eating disorders may not be to blame. One downside of this is that it could be interpreted as “if it’s genetic, then there’s nothing I can do about it”.

I think this is a defeatist perspective though. Whilst there are likely to be biological mechanisms that help explain the susceptibility towards developing eating disorders (and other behavioural disorders) they are often triggered by the environment of the individual.

What’s more the science of genetics and neuroscience is very much in its infancy, with studies showing associations rather than identifying causality. That is, they can tell us a wee bit about a person at one point in their life, a bit like a photograph, but they cannot explain their whole life. Rather, a holistic approach looking at how a persons' environment has changed over time is required to infer causality. This includes trying to identify specific triggers that could explain changes in an athlete’s behaviour.

As a coach, I certainly can’t change an athlete’s genes; however, I can influence how they are expressed. This is achieved through fostering an appropriate performance environment, helping athletes develop a healthy performance mind-set that considers that some people are more susceptible to eating disorders than others.

Deceptive Behaviour?

We all have a concept of ‘self’ that we attempt to portray to others. For example, when I go to arty-fart events, I wear different clothes and act more ‘intellectually’ than I would at a triathlon. In fact, I hide the sporty persona as I perceive that arty farts think competitive activity is abnormal. There’s no real harm in doing so. It’s what humans do to ‘fit in’ and to please others.

Athletes demonstrate similar behaviours when they wish to portray an image to their coach, i.e. to demonstrate that they will do what it takes to be the best they can be. That could be as simple as saying they feel motivated to do a session, to demonstrate commitment, even though they’re knackered and would prefer to be doing something else. Those with eating disorders may try to demonstrate “I've got a healthy relationship with food and I'm eating normally”. Outward signs will be sending different messages though. Despite what we’d like to believe, humans aren't really rationale creatures.

My mum died of a combination of emphysema and alcohol related diseases. Signs of her imminent demise were clear to everyone, but her condition was ‘medically’ reversible right up to the time she collapsed in a coma. Whilst my relationship with her wasn't great, I did everything I could to get her to stop smoking and drinking. I failed. Imagine a scene from Casualty. The consultant asked to see me for ‘the’ conversation. He was more uncomfortable than I was. Whilst my dad disagreed, I was all for switching off life-support as she had suffered significant brain damage.

Many years of alcohol abuse had damaged the way my mum thought and behaved. In life, she had become unable to make rational decisions. She hid bottles of gin behind the sofa thinking I didn't notice. Trying to mention things sensitively didn't work. Getting angry didn't work. Shouting didn't work. At the time, I was incredibly angry at her utterly selfish behaviour. The fact is that her excessive drinking had resulted in faulty thinking. What seemed rational to the rest of the world did not resonate with her.

It’s much the same with eating disorders, for both the sufferers and those close to them. Those with an eating disorder may demonstrate a fixation with food, subconsciously attempting to show to others that everything is fine. For example, bulimia sufferers may eat ‘normally’ but then make themselves sick when alone. Others see the obvious signs of excessive weight loss and changes in behaviour, but the sufferer continues with a veil of deception and lies.

Or do they? I think not. Whilst not negating the importance of taking responsibility for one’s actions, being in continual energy deficit affects all systems of the body including brain function. Behaviour is unlikely to be rational as a result. Sufferers subconsciously deceive themselves, using a form of cognitive dissonance. But they are not fooling anyone but themselves.

For others trying to help through reasoning and rationale argument, it is incredibly frustrating and upsetting. With my Mum, the doctors gave her drugs for her emphysema and asthma and treated her broken leg when she fell. The thing is, none of this would ‘rebalance’ brain chemistry and solve the underlying issues that affected her behaviour. Similarly, an eating disorder won’t simply be resolved through the promotion of healthy eating. It’s likely to require a very long-haul fix including extensive psychological/psychiatric support such as cognitive behavioural therapy (CBT). It’s a job for the professionals.

A Coaching Perspective

Being a coach is in an incredibly influential and privileged position as athletes often put their complete trust in you. The satisfaction of helping someone achieve their potential is amazing, but to achieve such success involves making many mistakes too. A top coach once confided in me about an athlete:

I pushed her really hard and she lapped it up. She was so tough and she seemed to be getting better all the time. Then she cracked. Her body had simply broken down and I didn't see the signs, despite them seeming obvious now. I fucked up.

To achieve sporting success involves coaches and athletes continually pushing the boundaries in search of the ‘red line’. Occasional going over this line is inevitable when highly motivated individuals are involved. In most cases, performance may suffer in the short-term but there will be no long-term consequences if the coach and the athlete are able to identify and reflect on mistakes made.

Weight management is very difficult for coaches to broach, regardless of their experience. It becomes even more challenging on some elite programmes when athletes are seen as a means to achieve ‘Key Performance Indicators’ rather than as individuals.

The best athletes are very good at reflecting as this allows them to explore options on how they can improve. They will often think more about what others say after the event. Whilst being a reflector is usually positive, it can also negatively influence self-perception and confidence levels. For example, highlighting the importance of achieving ‘optimum race weight’ could be interpreted by some as:

  • I need to be as thin as possible
  • They’re hinting that I need to lose weight

Misinterpretation of such well-meaning comments could trigger an eating disorder in an athlete, especially if they are genetically/neurologically predisposed towards getting one. Coaches are not the cause but they certainly can be the trigger.

Many coaches I know focus on the training prescription, such as training zones, periodisation and power meters. However, for me the role of a coach is also about delivering meaningful changes in the performance of their athletes through influencing their knowledge, beliefs, expectations and perceptions. That includes getting to know them as individuals, what their self-esteem is like and what motivates them. Any clown can prescribe 2 x 20 mins at Functional Threshold Power or write a swim-set on a white board!

Focussing on the individual is key as it opens good two-way communication. One athlete I coached worked in a male-dominated macho environment where body image was important. He was a rapid cyclist but his upper-body was too muscular! I had the data from body composition measurement to back my statements up and it was relatively easy for me to suggest that he needed to get lighter! The process was slow though, backed up by expert advice, specific goals and further body composition measurements. It worked too! However, my approach would be quite different with other athletes.

Nina’s quote re-enforced to me the importance of getting communication right and not making generalisations on weight management, especially when working with young motivated athletes, most specifically girls. Performance sports coaching is very male dominated, so many coaches do not fully understand the social pressures regarding body image that young female athletes face. In that context, it is very easy for a well-meaning coach to make a comment that may seem the most logical one in the world without considering fully how it could be perceived.

It’s unreasonable to expect coaches never to approach the issue of weight management though. That’s because it is such an important subject within the context of endurance sport. However, it must be considered in the context of the long-term development of the athlete. If a youngster is a few kg over-weight at 16 years old, then is this something to worry about? If an athlete is not the ’optimal body-composition’ and has not got a realistic prospect at performing at world-level, then does it matter?

Jodie Swallow

In researching this Blog, I came across another one, so eloquently written by Jodie Swallow. Rather than me going on infinitum, I suggest you read it as it’s more impactful than my blathering. I’ve picked out three quotes that I certainly can’t improve upon,

Thin can be fast, but so can strong, so can lean, so can healthy. Thin is not fit – strong is fit, lean is fit and healthy is fit
The difference between controlled nutritional strategy and a problem is small
Confidence is the key’. I would urge coaches, managers and federations to acknowledge this phrase and understand that it is an athlete’s attitude to herself that will result in longevity of high performance

This article had quite an effect on me. Many years ago, I remember almost falling off the chair with laughter when watching Question of Sport. The question related to Swallow being disqualified from a race for the letters on her race top being larger than regulation. Allegedly, this had occurred because her boobs had stretched her lycra top. It’s not so funny to me after reading her blog. Of course she’s been incredibly successful in long-distance events, attributed by some as her having a more optimal body composition. But I suspect it’s as much to do with having a healthy mind and body too.

Kirkland’s Tips

To summarise, I’ve included a table with my Top Tips in.

Periodise Nutrition

Achieving an ‘optimal’ race weight is both physically and mentally challenging. Therefore:

  • Any weight reduction programme must be planned so that losses are slow and safe.
  • Professional guidance from a registered nutritionist/dietician should be sought when possible.
  • As a rule of thumb, an athlete should hit race weight at least 3 weeks out from a targeted race. Power/fitness gains may be lost otherwise.
  • Rest periods when athlete shifts away from a ‘performance’ diet are desirable.
  • Binge and purge regimes should be avoided.


Coaches and other support professionals often forget about the psychological wellbeing of athletes and focus on what is best for ‘performance’. However, such a frugal existence is to psychologically challenging for some. The Brownlee’s love cakes and scones after all and I think they would be weaker athletes if they restricted such treats. Therefore:

  • The odd treat is fine. My finer half has a few squares of chocolate each evening.
  • Rewards and treats can become excessive and habitual though, so they care is required.
  • Fat per-se is not bad as long as it’s not highly processed or ingested in large amounts.

Weight Management Measurements

Body Composition

Most athletes and coaches like goals and targets and weight management is an area where specific goals can be appropriate. Many nutritionists and sports scientists are trained to measure body composition, in simple terms that is how to measure fat mass and fat free mass. The measurement is commonly expressed as % body fat. In cycling and triathlon, typical percentages for elite athletes are as follows:

Male: 5-11%; Female: 10-15%

Anything below the lower end of the range is considered to be unhealthy. It is also important to consider that some athletes need or are predisposed to have a higher % body fat than others. That means not everyone will be able to get to the lower end of the range and still maintain good performance and health. Regardless of the measurement techniques used, % body fat will always be an estimate based on prediction equations so many people prefer the sum of skinfolds method.

Pinch a bit of fat on your bicep and you’ll get an idea of how skinfolds are measured. There are very specific anatomical landmarks where measurements are taken, using highly accurate callipers, and then added together to give a sum of the measurements.

Measurement accuracy is key. Those who take anthropometric measurements should be trained to do so (by ISAK). A professional will always be able to tell you how accurate their measurements are, expressed as a % and they should be better than 5% accurate. I won’t talk about ideal ranges for the sum of skinfolds but I think that all serious athletes should be measured around 3-4 times per year. Too low a measurement will be a warning of potential very serious health issues.

Body Mass Index

Body Mass Index (BMI) is a way that many health professionals measure if people are a healthy weight for their height or not. It’s calculated as follows:

BMI = mass(kg)/heigh (m))2

I am 1.86m tall and have body mass of 83.5kg; therefore, my body mass is 24.14. Using the table below tells me that I’m a healthy weight for my height,

Category BMI Range

  • Very severely underweight <15
  • Severely underweight 15.0-16.0
  • Underweight 16.0-18.5
  • Healthy weight 18.5-25.0
  • Overweight 25-30
  • Moderately obese 30-35
  • Severely obese 35-40
  • Very severely obese >40

With such a simple method of calculation, which was developed over 150 years ago, there are bound to many limitations to its use. Ranges refer to a white non-athletic population and do not consider relative muscle/fat mass, so they shouldn’t be used carte-blanch to make inferences on athletes.

I suppose they are an OK guide for coaches that provide them with practical and relatively objective method to check if an athlete is a healthy weight or not. Some coaches set an arbitrary BMI target of healthy weight minus 1 but I’m not so sure if this is wholly appropriate.


In a coaching context, ensuring an athlete has a healthy mind and body always comes before targeting body weight. I believe that for most successful athletes, they need to display behaviours which enable them to push beyond the boundaries expected within population norms. That includes maintaining a healthy athlete’s diet and a relatively low body mass.

Of course, motivated people often push beyond safe boundaries so coaches must take care and be aware of how such behaviour in the context of weight management can have very serious health implications. The well-being of athletes as people comes first and performance is secondary, with absolutely no exceptions to this rule.

Knowing Nige Comes in Handy

About Me

I’m an endurance sport expert, who works as a Lecturer in Sports Coaching at the University of Stirling, Scotland’s University of Sporting Excellence. I am a BASES accredited sport and exercise scientist with Chartered Scientist status. I worked at British Cycling for 6 years as a coach developer and am a qualified triathlon and cycling coach. I have over 20 years’ experience in triathlon and an extensive personal network in the sport.

My coaching fees are commensurate with my level of experience, unless you can make me laugh and have the ability to win at the highest level. Then I’m cheap as chips.

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andrew kirkland

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