Carb-loading is often positioned as the holy grail of sports nutrition.
However, in my experience working with athletes, most have never implemented it in a structured way, beyond maybe having some pasta the night before a match.
And although it clearly isn’t going to solve all your nutritional requirements, it is worth delving into what it is, and where it should or shouldn’t fall into your nutrition plan.
Carbohydrates for Sport
When you’re making those blistering runs up and down the pitch, or doing tackling grids in training, or running a 5k PB, or completing a marathon, your body needs to create energy quickly and repeatedly, and for a sustained period, to keep up with those demands.
The optimal fuel source for this job is glycogen - a name given to carbohydrates stored in the body.
Put simply, when we eat carbohydrates, they are broken down into glucose, which is circulated around the body, and if not used immediately, can be stored as glycogen in the liver and muscles.
This glycogen is then available to be converted and used during intense activities like heavy running sessions and sporting matches.
The more glycogen you have available when it comes to match-day or race-day, the more fuel that will be available, and hopefully, the better your performance will be - or at least the less likely that low fuel availability will be your performance-limiter.
What is Carb-Loading?
Carb-loading (or carbo-loading or carbohydrate-loading) is a term that describes a strategy used to increase the amount of glycogen stored within the body leading up to a sporting event, by increasing carbohydrate intake in the days leading up to that event.
The original method proposed involved a few days of minimal carbohydrate intake with a lot of training to deplete glycogen stores, followed by a few days of extremely high carbohydrate intake and no training, with the aim of increasing glycogen storage through a “supercompensation” effect.
As you can imagine, this was logistically difficult, and for most athletes, probably a miserable experience, which is the last thing you’d want on match-week or race-week.
Sure, if you thought there was no other option and that it was going to reap huge performance benefits, you’d probably do it, but fortunately, researchers compared an approach of simply increasing carbohydrate intake in the 1-3 days leading up to the event, without the prior depletion phase, whilst decreasing training volume, and found that this was just as effective in increasing glycogen storage as the approach of going from very low-carb to very high-carb days.
Who Does it Work For?
Most of the research on carb-loading has been done on endurance athletes, who obviously have different demands than field sport athletes, for example.
The former involves staying at a steady pace for a long time, whereas the latter involves mostly short, intense, intermittent bursts followed by short recovery periods.
For endurance athletes, although the intensity may be lower, the consistency and longer duration often means that glycogen stores becoming low can be the limiting factor to performance, illustrated by the “bonking” or “hitting the wall” phenomenon you may have seen, where a runner can become unable to stand towards the end of a race, let alone run any further.
This usually isn’t a concern for the likes of field sport athletes, where even moderate levels of glycogen stores are usually enough so that glycogen won’t become depleted enough to cause the same level of fatigue associated with bonking in a marathon.
Still, there have been studies showing lower distances covered, and crucially, lower distances covered at high speeds, in soccer players with low levels of glycogen at the start of a match versus those who started the match with higher glycogen stores.
Even within the endurance world, carb loading is going to be more important for a marathon or ultramarathon than it is for a 10k or half-marathon, given the difference in how much fuel is required.
All of that is to say that whilst glycogen availability is more important for endurance sports, it is still important for athletes in shorter, more intermittent sports like GAA, rugby, and soccer.
Anecdotally, I’ve seen carb-loading to be an effective method of improving performance in the athletes I work with, many of whom are field sport athletes.
Even approaching it logically, given that glycogen is the predominant fuel source in high-intensity training and competition, it is likely that performance in these activities will be improved by having sufficient stores to pull from.
How to Do it
How Much?
For most athletes I work with, assuming we’ve already worked to build up a solid foundation of general nutritional competency, a carb-load approach will involve aiming to hit a specific carbohydrate target that will be higher than their regular daily target.
This will usually be in the range of 5-8g per kg of bodyweight for a field sport athlete (e.g. 375-600g for a 75kg athlete) on the day before a match, but could be as high as 10g per kg of body weight for an athlete preparing for a marathon (e.g. 750g for a 75kg athlete).
The range can also be affected by your current weight change goals.
For example, someone in a fat-loss phase may benefit more from a carb-load since their general carb intake (and therefore their general glycogen levels) are likely to be lower, whereas someone in a weight-gain phase is probably already eating enough carbohydrates so that their glycogen stores are sufficiently high without a carb-load.
Hitting these targets can be as simple or complex as you care to approach it, usually based on your current level of nutrition competency and how accurate you want to be.
For example, it may be as simple as increasing the carbohydrate portion of each of your meals and snacks the day before the race/match.
Others may prefer to follow a pre-planned meal layout built to give them the required number of carbohydrates.
Others still might prefer to track their food intake using an app like MyFitnessPal or Cronometer, aiming to hit a specific carbohydrate target in grams.
I recommend everyone try the latter approach at least once, given the learning opportunity associated with seeing the carbohydrate content of various foods as you track them - this will also set you up better to use the other approaches.
These intake targets might feel very high when you see how much food is involved, and if that is the case, you can always start at a lower intake and you’re still likely to get some benefits provided it’s above your usual intake.
What Types of Food?
Sometimes athletes will use a carb-load as an excuse to over-consume food in general.
Instead (and since you’ve gone to the effort of reading this article, you’ll probably already be in this mindset) I’d recommend viewing it as a strategic approach to improving athletic performance.
That means being selective about the food choices that make up the carb-load.
For example, optimally, the increase in food intake should be only in the form of carbohydrates, whilst keeping your fat and protein intake relatively constant, or even decreasing them compared to your usual intake.
The aim is to increase carbohydrate (glycogen) stores in the body - extra fat intake isn’t going to help with that, but will provide additional (and potentially excessive) calories, on top of the already high levels, which could lead to unwanted body fat gain or get in the way of your body fat loss goals.
High fat intake may also lead to digestive issues when paired with the high carbohydrate intake, since fat can delay the digestion of the carbohydrates, making it harder to consume the high amounts of carbohydrates and/or leading to digestive upset.
In order to manage this, it is better to opt for carbohydrate-dense sources, like rice, pasta, potatoes, cereals, breads, as opposed to things like pastries, curries, pizza (unless you’re selective with toppings to limit fat intake), foods with creamy sauces, and deep-fried foods, which, whilst they may contain carbohydrates, will usually also contain a lot of fat.
Additionally, whilst generally consuming high amounts of fibre is advised for its health and digestive benefits, during a carb-load, fibre can have a similar effect to fats, delaying the digestion of the carbohydrate-rich foods you’re consuming.
For that reason, some foods that are usually considered healthy, including whole grains and vegetables should be limited during a carb-load, or at least not increased in line with the increase in carbohydrates.
On the flipside, some of the foods usually thought of as poorer food choices, like sweet breakfast cereals, sugary sweets, sports drinks, and fruit juices can be used during a carb-load as easy-to-consume sources of almost completely carbohydrates.
Not only are these usually easy to digest, but also tend to be easier to eat per gram of carbohydrate even when hunger is low, due to their sweetness and texture.
As a final note, any extreme change in your diet can lead to unexpected consequences, so whilst we know that carbohydrate-loading can be beneficial, it’s important to trial it before implementing it completely before important matches or races.
Example Carb-load
It might be useful to see what a day of carb-loading could look like, so I’ll give an example below.
Please note, however, that no foods on this are required foods, and just because a food is not on it doesn’t mean you shouldn’t eat that food during a carb-load.
I’ve also purposely left out any specific amounts so that it can be amended to your own specific targets.
Again, this is just an example of what it might look like:
Breakfast:
Oats
Blueberries
Protein powder
Orange juice
Lunch:
Basmati rice
Frozen peas
Seasoned chicken
Snack:
Rice cake
Banana
Honey
Dinner:
Pasta
Lean beef mince
Tomato passata
Snack:
Rice krispies with milk
Article Written By Conor O’Neill
You can find out more about The Everyday Athlete Program by going to everydayathleteprogram.com/coaching.