There have been a few cases in recent years of professional or semi-professional athletes being pushed to lose more weight with the idea that it’ll help them run faster. In these instances, it’s gone beyond the limits though and had negative health consequences, but it is a viable tactic.
We can be mindful of these errors, whilst still losing weight healthily to optimise both health and performance. Health should never be sacrificed for the sake of faster running, especially for amateur athletes like us.
Why lose weight?
A study testing the impact of weight on running time found that a 5% body weight reduction (from fat mass), caused test times over 3km to reduce by 3% on average. The same test method allowed a 10% weight reduction from fat mass to reduce 3km race times by 5%.
A harness was attached to a vest that runners wore on a treadmill, with a counterbalance taking the equivalent of 5-10% of their weight. The results were significant, and it was theorised that over longer distances the same weight reduction would have an even greater effect due to a slower onset of muscle fatigue.
If you were to run a 3:30 marathon now, the weight losses described above, even without any extra effect for the longer distance, would mean you could potentially run 6-10 minutes faster. Not bad right?
Higher speed and endurance on race day can be benefits of losing weight in the right way. It comes down to moving less body mass however, if the wrong type of weight is lost, you’ll end up sluggish in your run time and the way you feel overall too.
Fat loss, not weight loss
The whole topic of weight loss is a bit misleading in reality. Having worked in the weight loss industry for 6 years prior to becoming a running coach, it’s a public education dilemma that was a big part of my reasons for switching focus in my work. What we really want to do is lose fat. Losing weight is relatively simple, fewer calories in, more calories out. Losing fat and maintaining or even gaining muscle at the same time is far trickier, but absolutely possible, even for us runners despite what you may have heard or read.
By losing fat and keeping hold of all your muscle mass, you can drastically increase your power to weight ratio, which is where you’ll gain a whole load of speed and endurance. There are safe ranges of body fat depending on your gender and age, so keep these in mind. As I mentioned at the start, your heath is more important than your fitness.
Read my other blog posts on the topic of weight loss for runners to see what steps to take to get these kinds of improvements for yourself.
Written by Kyle Brooks, Running Coach based in Norwich, Norfolk