The optimal body weight for a marathon
by Dr. Katrin Stücher

“Until my marathon, I have to lose a couple of kilos!” or “I notice every extra kilo when I’m out running!”.  Those are the sentences that you hear quite often by long-distance athletes.  But the question lingers, what is the optimal body weight for a marathon, or is there even an optimal body weight one can have for a marathon?

Whoever runs the 42,195 km by a marathon has to carry his or her body weight the whole distance.  That is why is it logical, that the light you are, the faster you are.  A study by the American scientist Paul Vanderburgh proved that by every kilo less weight, is 2.5 seconds won per kilometer.  Also, by weight reduction one maximizes the oxygen intake (VO2max), one of the most important parameters for running.   This means, the less weight you are carrying, the most oxygen your body can take in by every breath.  But be careful, weight is not weight!  By cutting down your weight, many runner risk muscle loss, because they do not provide their muscles with enough energy.  By not providing their muscles with enough carbohydrates, it leads to running on an empty tank.  Your body needs the necessary energy for body cleansing protein that the muscle cells or the immune system produces.  Next to the glycogen storage, the protein and functions structure would be break down, which leads to a higher change of infection and a weaker immune system (immune suppression).  If the glycogen storage cannot be filled up due to insufficient carbohydrate fueling, your performance levels will sink by intense activities.  If the need from protein is not covered, you can damage the functions structure suck as muscles, immune system, skeletal etc. no longer built up e.g. no regeneration.  All in all, the body will be weakened and the trainings and competition stress will no longer have a positive effect.  Instead, the body goes into survival mode and starts to burning muscle as energy.


Taking a closer look at Paul Vanderburgh’s study, made it clear, that just by reducing weight alone leads to the loss of muscle.  Through improving one’s condition, it’s important to have a higher percent of muscle by a small body weight.  During his tests, Vanderburgh made the Thesis:  Whoever wants to lose weight and wants to be faster, has to lose fat and should not lose muscle mass.  In addition to this, you shouldn’t be under the minimum Body Mass Index (kg/m2) of 18,9, otherwise it can lead to being severely underweight (Anorexia).


Another deciding point in the marathon training, is that through weight loss alone, one cannot achieve the optimal performance.  You shouldn’t incorporate weight loss during the trainings phase where you are training in a high intensity or stress.  The optimal performance generation is always the main priority in order to reach your marathon goal and to finishing your marathon training feeling great.

If you want to optimize your marathon weight, there are a few things you have to take into consideration.  One being, giving yourself enough protein and carbohydrate, so that you don’t risk muscle loss, this is one of the highest priorities.  At the end of the day, it’s not about your weight goal, it’s about the marathon time and this can only be reached through properly trained muscles and a healthy and injury-free marathons training.  That is why it is imperative to try and reach your optimal marathon weight.  To find out your optimal marathon weight, you can use a bioelectric- impedance- analysis and an individual nutrition strategy plan.


Katrin hat ihre Leidenschaft zum Beruf gemacht. Als studierte Ernährungswissenschaftlerin und durch ihre derzeitige Doktorarbeit in der Sportwissenschaft ist sie die ideale Ansprechpartnerin für alle Fragen rund um die richtige Ernährung im Trainingsalltag und im Wettkampf von Ausdauersportlern. In ihrem Kundenstamm sind bereits zahlreiche Erfolgsgeschichten von Podestplätzen bei Marathons, Ironmansiegen bis hin zu Podestplätzen bei der Ironman Weltmeisterschaft auf Hawaii vertreten.

Die studierte Ernährungswissenschaftlerin ist selbst begeisterte Läuferin und Triathletin und weiß aus erster Hand, worauf es im Trainingsalltag und am Wettkampftag selbst ankommt.

Unter bietet die Darmstädterin ihren Kunden ein breites Leistungsspektrum rund um die optimale und individuelle Ernährung an. Insbesondere bei Vorerkrankungen oder immer wiederkehrenden Magen- und Darmproblemen im Trainings- und Wettkampfgeschehen ist Katrin die ideale Ansprechpartnerin und weiß genau, an welchen Stellschrauben sie drehen muss, damit Sport und Ernährung im Einklang zueinander stattfinden können.

Katrin Stücher (Foto: JFQPhotos)