Later Blog Posts    

Earlier Blog Posts    







Fuelling your performance

The world of sports nutrition is constantly evolving, with new each new bit of research giving us more insight into how we can utilise the power of food to maximise performance. The problem that athletes and scientists face is that our current knowledge, while being incredibly detailed, is nowhere near complete.

This leads to problems when athletes attempt to choose the right nutritional strategy to complement their training regime. Here we will consider the subject of fuel for endurance performance.

It has long been accepted that carbohydrate gives you energy and fuels performance. This theory was largely based on early work in Scandinavia (1, 2), which showed that prolonged strenuous exercise performance was related to initial levels of muscle glycogen (the body’s carbohydrate store) and that increased perception of fatigue as exercise wore on mirrored the decrease of glycogen stores.

Over the years, this led to the belief in the scientific and athletic communities that high carbohydrate diets were essential for performance. In recent years however, some athletes have started to question the common wisdom and experiment with diets containing less carbohydrate and more fat.

Recent research suggests that having lower carbohydrate availability during exercise can actually increase adaptations to a training session (3). Desired adaptations such as increased mitochondrial enzyme activity and content, enhanced lipid oxidation (using fat as fuel) and improved exercise capacity have all been demonstrated with low carbohydrate training.

Although these heightened adaptations have been observed many times in labs, it has not yet been shown that a low carbohydrate diet promotes better exercise performance. As a result of this, the concept of ‘train low, compete high’ was born. In this protocol, a proportion (50-100%) of training sessions are completed with low carbohydrate diet, but athletes ‘refuel’ prior to competition to reap the benefits of their low carbohydrate training routine.

The field of exercise performance continues to advance all the time, with new developments giving rise to different strategies all the time. The ‘train low, compete high’ strategy is probably the most effective according to the current research, but time will tell if it becomes superseded by other novel and creative nutrition strategies.



  1. Ahlborg, B., Bergström, J., Ekelund, L.G. et al, Muscle glycogen and muscle electrolytes during prolonged physical exercise. Acta Physiol Scand. 1967;70:129.

  2. Bergström, J., Hermansen, L., Hultman, E. et al, Diet, muscle glycogen and physical performance. Acta Physiol Scand. 1967;71:140.

  3. Bartlett, J., Hawley, J., Morton, J. Carbohydrate availability and exercise training adaptation: too much of a good thing? Eur J Sport Sci. 2015; 15 (1): 3-12.

Posted By: Rob Fowkes
Posted: 21 Apr 2015