This blog is a bit different to my usual. We look at what food does for us, and the implications of this: including a brief look at the issues associated with Low Energy Availability (LEA). A conceptual framework if you will!
So, what does food do?
A 1,000-mile view (which is all we are addressing in this blog) of an athlete and food is modelled in the graphic above. An athlete is alive, trains and recovers from training. And food has multiple roles in each of these processes that can summarised as providing:
1. Fuel: aka calories, to produce the energy to do the things we need to do … be that just to breathe to stay alive, through to powering an explosive lift in training!
2. Building blocks: to repair damage, maintain and adapt the body … to the wear and tear of life and in response to training
3. Signalling: to the body about how much and what type of energy, building blocks, vitamins, minerals and other nutrients are available … and so how the body can fuel and build itself.
As point 3. hints at, there is continual feedback in the process. The body can use fuel and building blocks differently depending on what is available. And this in turn can impact how the body repairs, adapts and fuels and, as a result, can alter how it will use food in the future. And so on. And so on! In other words, by manipulating the amount and types of food available to the body we can impact what the body can do and how it does it.
The body has remarkable plasticity.
We can train, adapt and survive with multiple different diets. Yes, different diets might give ‘better’ training, adaptation and survival and these may differ between individuals. But we can do pretty well in each of these areas on some quite different diets.
Especially if we are not an elite athlete trying to get every millisecond or extra gram out of our training to win. Take a vegan versus an omnivorous diet, for example. There is a big difference in food types eaten if you exclude versus include animal products in the diet. But vegans and omnivores can both be healthy and perform well in sport.
Often the body can find different ways to achieve the same end, although it might be more or less costly down one route or another. For example, the body can use fats or carbs in aerobic respiration … carbs require less oxygen and so produce energy more efficiently, but both work and both have a place in survival, training and adaptation.
Bank accounts and trade offs
If we take away the signalling element for a moment and focus on the fuel and building block aspects of food, we can think about it like a bank account. We take in a certain amount of food. That is how much we have in our bank account. Now our body must ‘decide’ how to spend that food.
The fuel used for training is, largely, driven by an active decision by our brain of how much training we will do. Yes, how much fuel we spend will be influenced by how much is in the bank account (as an extreme example, if you haven’t eaten for 24 hours and try and do a marathon you are likely to struggle!), but for the most part it is our active choice how much is spent on training.
Beyond this, we don’t ‘actively’ decide how food is spent by the body. What is left after training is used for life and recovery, based on some sort of priority or dominant signalling in the body. We certainly don’t understand what and how these decisions are made yet – much more research is needed.
What does become obvious when we think about food like a bank account is that if we don’t have enough left in the account for optimal life and recovery, some things ‘won’t get done’. Because our body simply doesn’t have the resources available.
This is highly relevant for athletes, particularly those seeking a lean physique. A lean physique is not necessarily an issue. Athletes can be lean and healthy. However, particularly in sports with high energy expenditure, it can be surprisingly easy to descend into issues of Low Energy Availability (LEA), aka insufficient resources, without even realizing.
What is LEA? It is where an athlete consumes too few calories for their needs such that, after the calories burned in exercise have been taken away, they don’t have ‘enough’ calories (energy) left to support all the normal functions of the body.
What does this mean? It means that the body has to stop doing some of the things it needs to for full health. This ranges from proper immune function, to digestion, to the heart and blood vessels, to bone health, to muscle maintenance, to bone health, to hormone regulation.
It is easy to see how these can impact short and long term performance, let alone health. For example, increasing the risk of missed training days due to sickness, or bone breaks, or reduced performance because of loss of muscle, and so on.
What are the signs of LEA, so you can watch out for them?
Interestingly perhaps, you don’t have to be losing weight to be in LEA. If the body has reduced the energy it is using on normal bodily functions you can maintain the same bodyweight whilst still not having enough energy to function optimally.
Other signs include:
Frequent or persistent soft tissue injury or fractures
Increased number of colds, other viruses and infections compared to normal
Persistent tiredness or fatigue
Failing to improve as expected with training programme
Irregular or missed periods (females)
If you have multiple of these symptoms, you may need to consider the risk of LEA and seek help to walk the narrow tightrope between sufficient energy intake to maintain health and performance over the long term, and short term physique or performance goals.
The one bit of the graphic we haven’t explicitly talked about yet is body composition. It is implied when we think about the use of food as fuel and building blocks, but let’s touch on it a little more.
If we have the appropriate building blocks and fuel available, then our body composition will be impacted by the training stimulus we give the body. For example, if we are lifting heavy weights in an appropriate training programme, we are likely to build muscle.
Total body fat is dependent on the amount of food we take in, compared to how much we can use as fuel and as building blocks for functional tissue. If we take in excess we will store it as fat. If we take in too little, then we are likely to lose fat (note: it is possible to lose fat without descending into LEA, but of course the risk increases the less food we take in, the leaner we are, and the more we train).
In summary, we are quite literally what we eat. And therefore, what we eat has the potential to impact how we survive, train and adapt. It is all about trade-offs, balance, and also plasticity. All in all, the body is pretty remarkable!!