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Find it difficult to stomach race nutrition? What's the solution?

Nutrition Articles

I’m having issues getting energy, what’s the solution?

Your stomach and gut works a little like a sieve. If you pour water into it, the water passes straight through without any problems. If you pour a milkshake into the same sieve, it will pass through, but will take a little more time and will slowly drip. If you throw solid food into a sieve, it stays exactly where it is. The only way to pass solid food through a sieve would be to mix it up with water and make a thin enough solution, which could then start to drip through. The solution which enters your stomach, is therefore very important in terms of performance. During endurance events, we eat and drink to get energy, but if the food sits in your stomach, then you aren’t actually getting any energy into your bloodstream. Not only are you receiving less energy, you are also likely to get some kind of stomach problems, because you're clogged up!!

Isotonic is just the tonic

Isotonic refers to a solution which is a similar concentration to fluids in the body. Solutions of 7% are generally referred to as isotonic, this means that 7g of carbohydrate in 100ml of water is isotonic. You can count grams and millilitres as the same thing, so the calculation is simple, 100ml / 7g = 7%. Drinks bottles generally come in 2 different sizes, 500ml and 750ml so based on the 100ml / 7g rule, the calculations would be as follows:

500ml water + 35g carbohydrate = Isotonic

750ml water + 52.5g carbohydrate = Isotonic

Some solutions are less concentrated than isotonic fluids. For example, water has no carbohydrate in it and no calories, this is classed as hypotonic (hypo = low / less than). Solutions which are more concentrated than isotonic fluids, are classed as hypertonic (hyper = high / more than). An example of a hypertonic solution would be a smoothie.

That’s fine for drinks but what about solid food?

Many athletes choose to eat solid food during their event. As stated above, anything which is above 7% solution is hypertonic. Therefore, all energy bars and solid food is hypertonic. This means that if you wish to absorb solid food effectively, you must add sufficient water to make a 7% solution. For example, a standard energy bar is approximately 50-60g in total weight. We said earlier that 7g in 100ml of fluid would be a 7% solution, so that means you would have to drink 7-800ml of water with each energy bar to make at isotonic solution (56g is 7% of 800ml).

In ultra running events, there's often solid food such as sandwiches at feed stations, so get into the habit of estimating the portion size, e.g. what does 60g of cheese sandwich look like! Eating sandwiches, pasta and cake can very quickly result in a large mass of food gathering in your stomach. As for gels, they work the same way. A single gel contains 20-30g of carbohydrate (you need to read the packet). A gel with 21g would require 300ml to make a 7% solution.

Why is solution an issue?

Taking energy bars, gels and other solid food provides energy, but you have to take a lot of fluid to create an isotonic solution in your stomach. If you fail to take sufficient fluid you will have a thick ‘hypertonic’ solution in your stomach which may not digest and may well lead to stomach problems. Drinking enough fluid is critical for both energy supply and avoiding stomach upsets and bloating.

Don’t forget the 60g per hour rule

It’s unlikely that you can absorb more than 60g per hour of carbohydrate so eating too much food can have a negative impact upon digestion. Eating too much may lead to food gathering in the stomach and leading to feelings of bloating or sickness. The carbohydrate ‘maltodextrin’ seems particularly prone to doing this and all carbohydrate drinks and gels tend to consist of maltodextrin (pretty much every energy drink on the market is the same, it’s flavoured maltodextrin).

Practical advice:

  1. You need to stick to the 60g per hour limit for carbohydrate intake. Less than 60g is not enough and more than 60g is too much.
  2. A solution of 7% is not always attainable, aim for 10% as a start point for intake, for example:

60g energy powder + 600ml water per hour

60g energy bar + 600ml water per hour

60g of gels (2-3) + 600ml water per hour

  1. You can mix the above, e.g. 30g carbohydrate powder and 30g gels every hour, plus 600ml of water.
  2. Think about what’s the easiest to calculate and what the easiest to obtain during the event. Knowing how much energy is in drinks which are handed up at aid stations or adding your own powder on the go is not really feasible so gels and bars are often simpler to use and to quantify. In truth, you really have no idea what’s being handed up in the drinks bottles, so water is always the safe option because you know what you are getting.
  3. Feeding is easier when cycling compared to running, so if you’re doing Ironman triathlon, the bike feeding is critical to set you up for the run. If you're running an ultra, the slower pace can help, but little and often applies.
  4. Little and frequent works best for digestion. A gel every 20-30 minutes or half a bar every 30 minutes is better than a full bar every hour. You still need to drink the correct amount of water to account for solution.
  5. Drinking water only with bars and gels has the benefits of ‘freshening your mouth’. Energy drinks, gels and bars can leave you with a constant sticky taste.
  6. If you rarely suffer stomach issues, then you may not need to target a 10% solution. You may find that 600ml of fluid is too much (especially in winter) but the above figures are largely aimed at those who do suffer issues.

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