What would be the best type of carbohydrate for an athlete to eat before a long training session?

Carbs and the role they play in the diet can be confusing if you over think it.

Its not a matter of cutting them out completely or overloading on them at every meal but including them at effective times to prepare for the training session you have coming up so you can appropriately pre load energy to burn.

Planning and preloading fuel stores to prepare for training & competition so you have energy to burn is just as important, if not more important, as considering what you will eat after you have trained to recover when you finish.

Having fuel from carbohydrates available to use effective for performance is especially important in high intensity, short burst activity where glucose is the primary fuel source for peak power and equally important with a multi-day event or high training load which involves multiple sessions a day. Some athletes may be unsure and either eat too many carbohydrates and feel full and lethargic or not enough and feel flat. How much exactly in total will depend on athlete body size, training and performance goals.

The amount for an 80kg athlete with moderate training can range between 300-500g of carbohydrates.

This is best distributed over the day through regular snacks ranging between 30-60g of carbs and pre training meals (3-4 hours before) up to 80g of carbs.

Keeping carb stores accessible and regularly topping up energy is far more efficient for the body to train for performance rather than depleting all stores, performing poorly, and having to eat excessive portions at night to make up for what you have missed during the day to regain some energy which may not meet performance or physical goals you are working towards.

Having a substantial good quality carb load in the hours before you train, during a training session that goes longer than 90 minutes, very high intensity session or back to back training session will help to boost carb stores for the training session you are about to do.

The options below include carbohydrates to have at main meal and also some simple low fibre, low fat, high carb options for an added energy boost before a training session is done – these are particularly good to have during back to back session or before early starts to get your body started.

The following list demonstrates some portion sizes of carb foods so you can see if you are having either too much or not enough when you eat. Note that this suggestion is just the carb component of the meal and not a whole meal, which means total kilojoules for each suggestion will vary.

15g Carbohydrates

• 1 slice bread
• 1 oat based muesli bar
• 3 milk arrowroot biscuits
• 1 cup fresh fruit salad
• 1 large apple

25g Carbohydrates

• 1 sports gel
• 2 fresh dates
• 1 Tbs Honey
• One serve of Musashi Bulk Protein

30g Carbohydrates

• 2 thin slices of bread with 2 tsp honey
• 400ml orange juice
• ¾ cup cereal with light milk
• 1 pita wrap or tortilla
• 2 regular slices raisin bread
• 220g tin spaghetti
• Banana in a slice of bread
• 4 corn thins + 2 tsp honey
• 500ml Powerade
• 2 large slices of bread (Helga’s)
• 200g tub low fat yoghurt
• 7 corn thins or 6 cruskits
• 2 scoops of Powerade powder
• Muesli bar + large piece of fruit
• Tubes of custard + piece fruit
• 2 oat based muesli bars
• 7 jelly babies lollies
• 1 large bread roll
• ¾ cup cooked pasta
• 1 cup sweet potato 

40g Carbohydrates

• 2 slices of bread with jam
• 1 cup cooked pasta
• 1 banana in a bread roll
• 1 packet low fat 2 min noodles
• 3 scoops Powerade powder

60g carbohydrates

• Large banana and a 600ml Powerade
• 5 thin slices of bread
• 4 slice bread + 1 piece fruit
• 2 bread rolls with sandwich fillings
• 200g yoghurt and 1 cup tinned fruit OR fruit salad
• 4 cruskits and 500ml Powerade

80g Carbohydrates

• 2 cups cooked pasta
• 1.5 cups cooked rice
• 1 cup cooked rice and a tortilla
• 1.5 cups pasta + 1 large potato
• 1.5 cup pasta + 2 slice bread
• 2 cups nutri grain
• 7 weetbix with milk

Eating around competition & fuelling long sessions

Having glucose available to use is far more efficient and effective for performance so there is fuel ready to be used. This is especially true in high intensity, short burst activity where glucose is the primary fuel source for peak power.

If training with low levels of carbohydrates the body may turn to breaking down muscle to get through the session, or slow down to match limited energy present.

Having a substantial good quality carb load in the hours before you train, during a training session that goes longer than 60 minutes or is very high intensity means the body has fuel available to push itself more and perform better. This also includes having a top up of carbohydrates during a back to back session like gym and then a skills session.

For an added energy boost before that second effort is done, have a simple low fibre, low fat, high carb options like a banana, cruskits, powerade or any of the options above, up to 1g/kg body weight, to help maintain energy stores through the session rather than trying to chase your tail after training or competition is done.

Deciding how to approach nutrition in the few hours before a training session or race is one of the great fueling challenges for athletes. To help you hone your own pre-workout food intake, I've drawn on my MANY years of experience of honing my own strategy and looked at what scientific evidence says about what, how much and when you should eat before exercise...

I’m definitely a “Lark” to use a term borrowed from Matthew Walker’s brilliant book ‘Why We Sleep’. Because of my natural chronotype I have a tendency to start the majority of my workouts well before 7am, and occasionally before 6 (to the annoyance of my wife if my alarm is set too ‘loud’).

One knock-on effect of being an ‘early bird’ is that I tend to do most of my training on an empty stomach (except for a mandatory coffee) because both the thought and practicalities of eating anything significant before getting out of the door is quite unappealing at that time of day.

This approach works fine for me as most of my sessions are only up to about an hour long. Whilst I'm sometimes very ready for breakfast by the time I finish, it rarely feels like not eating beforehand is diminishing the quality or enjoyment of my training. I probably benefit from the fact that I’ve become habituated to this approach over many years, so physiologically and psychologically, it’s ‘normal’ as far as my body is concerned.

However, I do make a conscious effort to eat something quite carbohydrate-dense before a race, or any longer training session (~90 min or more), in order to ensure I’ve got sufficient energy to perform at my best. My current go-to before a long bike ride is a bagel with nut butter and honey. Without this, I find myself flagging late in the session.

The peer-reviewed science agrees that eating something carb-dense beforehand is basically a sound approach. In fact, the opening lines of a 2014 paper on the subject state:
“Carbohydrate feedings prior to endurance exercise are common and have generally been shown to enhance performance”.

Image Credit: Unsplash (copyright free)

How much carb should you eat before exercise?

The general recommendation for pre-exercise carb intake to maximise endurance performance is to ingest 1-4g of carbohydrate per kilo of body weight in the 1-4 hours prior to the beginning of exercise.

The mathematically inclined will have immediately figured out that these recommendations cover a broad target area; clearly chowing down 4g per kg around 1 hour before starting exercise is a very different proposition to nibbling just 1g per kg 4 hours before!

Despite their wide range, these guidelines do highlight the rough ballpark within which most athletes should be aiming to fit in their pre-exercise carb consumption, with the details to be refined through a trial and error process over time.

Clearly, for most people it will make sense to consume more (i.e. closer to 4g / kg) the further out you are from starting exercise but, if the pre-exercise time frame is more compressed, then taking in less is more likely to be appropriate. It also seems logical to assume that a more aggressive approach to pre-fueling is warranted for longer and more intensive efforts, whereas a lighter feed is probably appropriate for shorter or easier events.

The theory (one that seems to be borne out in practice) is that this level of carb intake ensures adequate energy availability - and ‘tops off’ liver glycogen stores in particular - if the event is first thing in the morning. These will have been more heavily depleted than muscle glycogen stores overnight because, whilst your muscles basically rest at night, your brain still needs fuel and this is ultimately drawn from liver glycogen.

It’s also worth mentioning that these recommendations make the assumption that your muscle glycogen stores have been adequately topped up in the 24-48 hours prior (the ideal window for carbo loading - the subject of a different article).

The best pre-exercise foods

Most experts agree that there’s a lot of personal preference (and a certain amount of superstition!) that goes into determining what constitutes the perfect pre-exercise food choices for an individual. With that being said, there are some fairly universal characteristics of suitable pre-exercise foods and these include:

• A high proportion of simple/digestible carbs (i.e. relatively low in fat and protein), to aid rapid digestion
• Low in fibre (for ease of digestion and to help avoid GI discomfort)
• Relatively ‘plain’ in taste (in general, simpler fare is easier to eat, even in stressful situations)
• Familiar, tried and tested in the past (to avoid any unforeseen negative consequences when the stress of race day is thrown into the mix)
• Easy to prepare on the spot, or to prepare in advance (to reduce unnecessary stress related to getting things ready in a compressed time frame)

My own go-to choices for a pre-exercise meal include porridge (oatmeal) with added honey or sugar, flapjack or oat-based energy bars, white bread or toast with honey or jam. Before longer events I frequently add some nut butter to help achieve a feeling of satisfaction or fullness and to help avoid my blood sugar spiking too much.

I’ve eaten some basic combination of the above before the vast majority of my biggest training sessions and races for a number of years now and find it to be a reliable way to start full of energy, but not bloated or feeling sick. The typical carb content of these foods are listed in the table below to give you some sense of the amount of each you need to eat to hit certain carb targets, based on your body weight.

Timing your pre-workout meal

The exact timing of the pre-race meal is something that’s very individual and depends on two key factors:

1. The availability of feeding opportunities in the few hours before exercise
2. How much time you feel you need to leave between finishing eating and standing on the start line.

Personally, I’ve never really had a problem with eating relatively close to the start (i.e. within the last 90 minutes or so) but given the choice I’d probably aim to finish the bulk of my intake about 2 hours out. Others need closer to the full 4 hours to avoid bloating or a stitch.

This is something you can only really learn by trial and error so it’s important to play around with timings to find out what works for you.
As already discussed, the commonly cited ideal window for the majority of pre-exercise carb intake is between 1 and 4 hours before the gun goes off.

The main reason for leaving at least a 60 minute buffer between your last substantial intake of food before a long or hard effort begins is simply to allow time for digestion and reduce the risk of GI distress, sickness or bloating during the early part of your race.

Find a strategy that works for you

Many athletes, myself included, also like to take a final little dose of carbs (usually about 30g in the form of an energy gel, or some concentrated sports drink) in the last 15 minutes before the start. This is so that the dose hits your bloodstream quickly, sparing your stored glycogen stores for use later on. I’ve always found this to be a good idea before very long races, where maximising fuel stores is a key determinant of success.

Image Credit: Ryan Sosna Bowd ©

This final ‘top-up’ is not universally popular though, and the main reason cited by those who don’t favour it is a phenomenon called ‘Reactive Hypoglycemia’ which can sometimes occur once you get going.

Reactive hypoglycemia (sometimes also called rebound hypoglycemia, or postprandial hypoglycemia) describes a dip in blood sugar levels that can leave you feeling weak and shaky in the same way you do when you ‘bonk’, even though you’re not actually low on muscle glycogen at that point in time.

It’s thought that the underlying cause of this kind of dip in blood glucose levels during exercise is an excessive amount of insulin being released in response to carbohydrate ingestion, causing glucose to be removed from the blood at the same time it is also being used rapidly by your muscles.

As a result of this ‘double whammy’ effect, circulating glucose in the blood drops below acceptable levels for a period of time and you feel it as a horrible dip in energy, concentration and motivation. Whilst this often passes once your body resets itself, it can be unpleasant and potentially affect performance if severe enough.

Although it’s thought to affect very few athletes, reactive hypoglycemia is surprisingly frequently cited as a reason to avoid carb intake in the immediate run up to an event by many, as this quote from PH ambassador Bex Rimmington highlights:

The main reason [that I avoid carb intake immediately pre-exercise] is that I worked with a nutritionist who said that you have enough glycogen stores for the first 90 mins of exercise and that taking glucose immediately before the start causes a massive spike followed by an insulin response which can affect performance.

In reality - and as is the case with most aspects of pre-race feeding - figuring out your personal response to taking in a gel in the final 15 minutes before a hard effort is the key to deciding whether it’s something you should or should not be doing, albeit with the odds appearing to be stacked in favour of the idea that it will be beneficial rather than detrimental.

There’s no single right way of approaching pre-exercise feeding; it all depends on your individual physiology.

As an aside, continuous glucose monitoring (CGM) devices such as the Abbott Libre sensor - now being marketed to athletes by SuperSapiens - promises to help us work out our best individual approach by providing real time data on blood glucose responses to different foods and events. This is something we’ll be keeping a close eye on ourselves as it becomes more widely adopted.

Further reading