When we are out on the trails for long periods of times, we want consistent performance. To achieve this we need a constant supply of energy to fuel our movement. Without, some may manage better than others but there is no denying, those that nail their on the move nutrition, perform and also also recover better than those that don't. Demands vary for different athletes, hikers to runners, males to females but hopefully this will give you some useful tips to get you thinking about your personal needs whilst on the move on the trails.
Some basic science
Our body can use carbohydrate, fat and protein for energy. Good news, as it would be a poor survival system if there was only one energy source to rely on. The body tends to use carbohydrate and fat for energy. Although we use this mix of both energy sources, carbohydrate is the preferred source as it is more readily converted to energy than fat. We generally have a small amount of glucose circulating in the blood, with most being stored in the muscle and liver as glycogen. However, herein lays the problem. We only have enough stored carbohydrate to last about 90 min of exercise, compared to fat where energy stores should theoretically power a runner for at least 1300kms! So why use carbohydrate and not fat as our primarily source of energy? This is because carbohydrate is the most readily available nutrient and converted most efficiently to produce our needed fuel compared to how we utilise fat. If we take extra carbs when on the move we minimise this depletion by keeping the blood sugar level up, keeping stores a plenty and energy levels flowing. The long and short of it is, we need to provide the body with what it wants when performing under demand and energy needs are increased. So, the answer....take carbohydrate when exercising for longer than 90 minutes to preserve your muscle glycogen stores as long as possible and prolong your performance levels on the trails.
How much to fuel
It has been proven that the gut can process a maximum of 1g of carbohydrate per minute. This means, we can eat up to 60g of carbohydrate an hour to fuel us during exercise. Anything above this cannot be used and increases the risk of discomfort. However, during further prolonged exercise ( longer than 2.5hrs), if a “multiple” or “dual” carb source is consumed such as maltodextrin:fructose together, we can utilise up to 90g/hr instead of 60g/hr with a single source carb. This is because the two different types of carbs (maltodextrin + fructose) use different intestinal transporters for absorption hence increasing carbohydrate delivery and use. In reality though, this is a large amount of carbohydrate and probably not managed by many. Despite all these wonderful facts and figures, in reality, many find it hard to eat on the move and, I admit, it was something I struggled with tremendously when running in my early days. Not only the physical aspects of eating or drinking on the move but also the undesirable affect it can have on your stomach and have you dashing begins your nearest bush. The good news is, much like you can train your muscles to be stronger and fitter, you can also do the same with your gut. Taking small amounts of bars, gels or sports drink when you are exercising will slowly help you increase your tolerance to fuelling on the move.
When to fuel
Most of us associate fuelling during runs sports such as marathon running, however, if you are going to be on your feet for longer than 2 hours, anyone needs to consider how they are going to fuel their activity. Someone out doing a gently hike for 4 hours will of course have differing needs to someone our running in the mountains for 4 hours but careful consideration is needed for both. Studies show a performance benefit when taking carbs during exercise lasting longer than 60 mins. This is the point at which depleting glycogen stores start to affect performance, therefore extra fuel keeps blood glucose levels maintained. With this in mind, it is important to maintain your energy levels as early as possible. If you are waiting to take your first gel, bar or drink until an hour into your activity, your glycogen stores will already be getting low. The key is to start early at about 20 minutes from starting. Although you won’t necessarily be feeling low on energy, topping up the tank from the word go will only benefit you later in the race where fuelling may become harder due to fatigue and potential stomach problems.
The science provides the guidelines but be flexible, as no matter what the science says, you are more constrained on the day by what your stomach dictates.
Think about practicalities of what you are eating and drinking. Do you need to bring a water filter so you can have clean water throughout the day? Will you be stopping to eat or will you need food you can eat as you move?
You can use sports drinks, gels, bars, real food...whatever works for you. Just remember anything with high protein, fibre, fat content can slow absorption down. Take a look at our homemade gels in our blog.
Experiment during your training to see how much and what type of food you can tolerate.
To start, trial 10-20g carbohydrate per hour, little and often and aim to work up to 60g/hr….remember your gut is trainable.
Set your watch time to bleep every 20-30 mins to remind you to fuel.
Start fuelling early whilst the gut is fresh and absorbs carbs easily, things might not be so easy a few hours into the race!
The Golden Rule - if you have a target event or race, don’t do anything new on on that day. Practice in training and on the day all should fall into place.