The Underappriciated Consequence Of The Pursuit Of Fat Loss

Many cyclists look to maximise their performance by restricting energy intake, reducing their fat mass, and improving their power-to-weight ratio.

Whilst in theory, this is an effective way in which an athlete can improve performance, based on reducing weight whilst maintaining power, allowing an athlete to enhance their power-to-weight ratio, a key determinant of performance in many cycling disciplines. The view that lighter is better is often overly simplistic in the sense that there are several consequences associated with dieting that can negatively impact an athlete’s performance, and whilst weight loss may lead to a lighter athlete, it can also negatively impact an athlete’s ability to produce power.

Being in an energy deficit is also not a guarantee that it is simply fat mass that will be lost. Significant muscle and bone density, glycogen, and water weight can often be lost too. Its also worth bearing in mind that due to it's energy density, the loss of fat tissues requires the greatest defecit to shift the same amount of mass as say muscle. 

One of the key goals of training is to maximise the adaptive response of the muscle, one of the key processes that supports this, is called muscle protein synthesis. In simple terms, this is the process through which new muscle tissue is grown and is a key focus when looking to maximise training adaptations.

One of the significant issues with an athlete being in an energy deficit is that due to the growth of muscle tissue being quite expensive from an energy perspective, as well as muscle requiring a lot of energy to be maintained, when an athlete is in an energy deficit, it can lead to less energy being available for the maintenance and growth of new muscle, negatively impacting the adaptive response to training and even leading to the loss of significant muscle tissue, which can negatively impact performance.

A number of research studies have investigated this in athletes. A key study from Areta et al., (2014), showed that just 5 days of a diet that was low in energy was enough to reduce an athlete’s rate of muscle protein synthesis at rest by a staggering 27% compared to eating to energy balance. In the long term, this could have significant consequences on an athlete's long-term training adaptions and the performance gains they see from training.

Interestingly, though, the inclusion of resistance exercise, combined with protein, was enough to rescue some of this negative impact of dieting this combination was able to at least rescue rates of muscle protein sytehsis to that equivalent to rest in the high-energy group.  

As such, if you’re an athlete that is looking to improve their power to weight ratio, it’s important to consider the long terms effects of low energy availability on training adaptations. A key strategy to ensure you maintain muscle mass is to ensure you combine your training (including some resistance type exercise) with adequate intakes of protein, typically in the region of 2- 2.2 grams per kilogram body weight.

 Coach Ben

Reference

Areta, J. L., Burke, L. M., Camera, D. M., West, D. W., Crawshay, S., Moore, D. R., Stellingwerff, T., Phillips, S. M., Hawley, J. A., & Coffey, V. G. (2014). Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit. American journal of physiology. Endocrinology and metabolism, 306(8), E989–E997. https://doi.org/10.1152/ajpendo.00590.2013