Why eating less made me run slower...

The running world is slowly turning away from the belief that you need to eat less in order to run faster. There is more and more education around the dangers and the damage this can cause. However, this message can never be reiterated enough, because there is always someone who has a small voice in their head telling them it is true. I had that voice in mine for a long time, so are not alone. I hope this blog can help you realise why eating less won’t make you run faster.

No energy.
Eating less in order to loose weight and run faster may leave you feeling great for a short amount of time. This is enough time to trick your brain into believing you are doing the right thing and reinforce such behaviours. However, before long, your body will run out of energy, quite simply because you are not giving it enough fuel and it will go into conservation mode. Think of your body like a car. Without fuel, it literally cannot function. As a result, you will not have the energy needed to run fast, let alone train at the standard you wish to. When I was at my unhealthiest point, I did not have enough energy to even run 1 lap of a rugby pitch and my performance plummeted as a result.

Reduced focus/concentration.
If your body isn’t being given enough fuel, neither is your brain. Both need to be fuelled sufficiently in order for them to operate optimally. If we don’t provide our minds with plenty of fuel, it can be difficult to focus and concentrate. This can therefore make it hard to knock out solid fast sessions, as your brain just doesn’t have the mental energy to focus on the task ahead. Sessions can require a lot of mental energy, so you need to have a fuelled brain in order to get the hard work done. I found myself feeling mentally drained before the session even began, therefore I rarely had the mental strength to get to the end.

Trouble sleeping.
If your stomach is tossing and turning, you likely will be too at night. You may not think it, but sleep actually requires energy too. If you under-eat, there may not be enough energy readily available to support your sleep activity. Therefore you may struggle to get to sleep, but also to remain asleep for a long period of time. Additionally, if you find yourself waking up hungry in the night, your body is likely telling you that it needs more food. As humans, let alone athletes, we need plenty of sleep in order to meet the demands of training. When I was underfueling my sleep took a hit as my brain didn’t have the ability to rest like it needed to. This in turn leads to my next point.

Increased risk of injury.
If you are not sleeping well on a constant basis, you are not able to give your body the level of recovery it requires. A lot of our adaptation occurs overnight, and poor sleep will affect the rate of this. A lack of sleep may lead to poor recovery, which in turn contributes to a higher risk of injury. Additionally, an increased risk of injury comes from the added destruction that comes with under fuelling. If your body does not have enough fuel to function properly, it will not be able to repair your muscles and bones. Consequently they can become weak and fragile. This can thus lead to an increased risk of injury. It may also damage your bone health and physical health. For example, under eating may cause periods to stop, something I experienced in the past, which in the long run can affect bone health and make injury more likely. 
Loss of enjoyment.
This is a big one. Ultimately, the main thing that will make you run faster is if you enjoy what you are doing. If you are excited to get out the door and work hard, it won’t even seem like hard work. When I was underfueling, I lost all my love for the sport. This was because every run was a struggle. I didn’t have the energy to make even a recovery run feel easy. Consequently, my enjoyment levels were zapped because I didn’t have the energy to make running enjoyable. I also became difficult as a person because I was “running” on empty at all times of the day. This did not help me run any faster at all. 

There are many more reasons why underfueling can be damaging and hinder your performance, but I hope these give some insight into why it does a lot more bad than good.