The TRUTH about Carbo Loading

The TRUTH about Carbo Loading

There was a time when carbo loading was as synonymous as the race itself. That race, is obviously the Comrades Marathon. Carbo loading does not have the same cult following as it once did, but there is still a space for it, to some extent. This however, is what you really need to take into consideration.



David Katz: As we continue to build up to the Comrades Marathon here on 32Gi Sports Nutrition, Mark Wolff joins us again and a great topic today. Of course race week eating is so vital and it has over the years, the debate on what to eat and what not to eat has changed.

Carbo loading has become very important and as research has done, things change. All of a sudden that carbo loading which almost is synonymous with Comrades as running the race itself, Mark is not the way to go for everyone?

Mark Wolff: I agree with you 100%. It is a very debatable topic. Let’s look at how you should be actually feeling in race week. We mentioned in a previous podcast keep the meals small, keep them consistent and obviously keep them healthy. I think that’s very crucial. Make sure you hydrate all the time.

The whole truth, and nothing but…

When it comes to carbo loading one of the things is that many athletes or many runners let’s say, do not understand what the purpose is behind carbo loading, and actually how to carbo load properly before an event. We have to remember that the body has two primary fuel tanks, the one being glycogen which I always call your ‘rocket fuel,’ and the other one being your fat tank which is more like your diesel engine fuel.

Your rocket fuel or your glycogen tank will be utilised at a much higher rate when you’re performing at a higher intensity. In other words, when the body is sort of oxygen depleted, not getting enough oxygen to the system and in that case glycogen becomes a primary fuel.

However, Comrades is a very pace controlled event. You should be breathing very regulated and very controlled at Comrades. If you’re not, you’re actually going to be over-burning yourself. In other words, performing at too much of a high intensity and chewing up your glycogen stores quite quickly.

When you can control the pace and you can get oxygen into the system, you can burn off a higher amount or high percentage of fat as far as opposed to the glycogen and depending on the pace you go at, you can definitely burn off a lot of fat. You can look at the 80 to 20% mark. That means that Comrades Marathon is more of a fat burning event than a glycogen burning event and you need to treat it as such.

So what is carbo loading?

What is carbo loading? Carbo loading is really there to top up your glycogen stores. Glycogen stores, we’re talking about 2 000 calories usually with glycogen stores. Basically 2 000 calories is not going to fuel a Comrades Marathon. You need a lot more than that to fuel a Comrades Marathon, so you will be tapping into your fat tank firstly. If you can top your glycogen stores up just a little bit, it’s not going to make a major difference over a 90km race.

In actual fact, the only people that might benefit from slightly higher glycogen levels, but they still need to control their pacing very well in Comrades are the elite athletes. There you could be talking 1-2% differences or 0.5% differences, which could be the difference between maybe a win or a Gold Medal or something a bit slower than that. The thing is, in their cases maybe it could make a slight difference.

The problem is with carbo loading is that people generally tend to get it wrong. There’s three regimes for carbo loading. There’s one called the ‘classic’ regime, very, very dangerous, why? You completely exhaust your glycogen stores by doing exhaustive training. You deplete them completely and then what you do is you introduce low carb eating for a couple of days to keep those glycogen stores down. Then what you do is you increase your carbohydrate intake and you build up the glycogen stores in time for race day.

If you haven’t tried and tested this, you might get it wrong. You might not get your glycogen stores topped up, you might actually land up having them not topped up on race day and then you land up in big trouble. Unless you’ve practiced it, exactly what to do, I wouldn’t advise it.

There’s a popular regime called the ‘modified’ regime. There what happens is you actually, you do exhaustive training about 6-7 days out, but instead of moving to a low carbohydrate diet, you move towards more a moderate carbohydrate diet. You eat moderate carbs over a period of time and you increase the carbohydrate intake about 2-3 days before the event and then that also tops up the glycogen stores. Again, you have to have tried and tested it. You can’t just suddenly say: I’m going to carbo load if you haven’t done it before.

The traditional carbo loading technique

Then there’s the very popular ‘one day’ regime where athletes actually eat a low carb diet probably about 5-6 days before the event, they then increase their carbohydrate intake and then they massively increase their carbohydrate intake the day before the event.

I don’t like this very much because it’s not going to make a major difference on race day. By overeating that amount of carbs the day before an event, if you get it wrong, you’re going to feel a lot of discomfort. Your stomach is not adapted to that kind of carbo loading, you’re going to not feel happy at all and you can land up causing damage.

The ULTIMATE fuelling strategy

What do I suggest? What I suggest is that your overall calorie intake in race week should actually drop to the right level because obviously calorie burn rate is much lower in race week. You’re definitely not doing any major training. So you need to consume closer to what we call your ‘rest metabolic rate,’ which is the rate of calories that you burn more in a state of rest.

You can slightly increase your carbohydrate content. I like the moderate carb intake and then I would suggest that you can slightly increase it a day or two before, but again, the macro nutrients have to be in line. In other words the calories have to be in line with what your total calorie intake is.

You can’t go and eat the same and then increase the carbohydrates because you might be overloading on it. Keep it nice and consistent and gradually increase your carbohydrate intake, but very slightly and also to prevent insulin spiking and getting these blood glucose elevation, too much blood glucose elevation. That’s what I do suggest.

If you want to increase your carbohydrate content the day before the race, I always suggest, do not do it the night before the race. Do it at lunch time. If you want to have slightly more carbs, make that your slightly bigger carbohydrate meal the day before.

In other words at lunch time because if you increase your meal the night before the event, it will impact your sleep. You’re going to lie there, you’re going to feel digestive discomfort and it’s going to impact your sleep, you won’t fall asleep so easily.

Another thing that you need to focus on is definitely the hydration part. Don’t go and drink too much the evening before the race because what’s going to happen is you are going to also battle with sleep. You’re going to be running backwards and forwards to the bathroom because you’ve overhydrated. Don’t go and overhydrate just because you need to hydrate suddenly the night before, it needs to be consistent through the week and don’t overdrink before sleep.

How to avoid pre-race “Comrades belly”

Another thing to take notice of is that pre-race nerves and digestive impact are a very real thing. They can cause havoc with the digestive system. Everybody gets nervous before a race; even elite athletes get very nervous before a race. You can get symptoms and signs of nausea, diarrhoea, you can get stomach cramps, you can even get appetite reduction and there are a number of ways you can deal with this.

Firstly, keep your fibre intake low. Excessive fibre causes irritable bowel. You want to keep the fibre intake low. Avoid high fibre foods such as bran, high fibre breads for example or high fibre cereals. Don’t eat dried fruit, anything that’s high in fibre, try and avoid as much as possible so that it doesn’t irritate the bowels.

Just as a simple example, if you’re going to go and eat a high fibre bread such as a low GI or seed loaf, rather go with the white bread. Because it’s much lower in fibre and it will still provide you with the carbohydrate intake that you need.

If you battle with your appetite and you can’t eat solid foods, try and go for liquid foods. There’s nothing wrong with it. You can go with smoothies, porridge, cereals, soft dense foods are absolutely fine and there’s no issues there at all.

Get your Comrades pH balance right!

As far as the kinds of foods you should eat, you should try and focus also on pH balanced foods. In other words, try and eat more alkaline foods in your diet as opposed to acidic foods. Acidic foods do cause inflammation. They do cause things like reflux. They can cause irritable bowel. Alkaline foods suppress it; they also keep the immune system quite nice and strong. I would actually recommend trying to eat more of an alkaline based diet and by the way, if you are drinking coffee, understand coffee is acidic. Caffeine is acidic.The thing is that you need to understand, don’t go and drink stimulant drinks in excess because it can increase the acid in the bowels.

From a hydration point of view, very crucial, I’ve mentioned it quite a number of times. You do lose fluids in the form of sweat, if you’re exercising. But if you’re not exercising, you’re still losing it in the form of urine and faeces etc. You do need to keep hydrated. Make sure you hydrate from the morning all the way through to the evening and like I mentioned earlier, try a hypertonic drink because that will benefit you quite nicely from a hydration perspective.

I hope this has been valuable and try and plan your week as carefully as possible. Don’t let there be surprises. The better you plan, the less stress there is. The more you depend on exactly what you’ve taken with you down to Comrades to eat and to drink, I can absolutely assure you, it will make a much, much better day out.

DK: Mark, it’s been extremely helpful and you do have some great visual representations of the different regimes, the classic, the modified and the one day regime which I’ll put a link up to your blog, The Fitness Freak, will give you all the info there as well. Thanks for tuning in and be sure to check out our other podcasts in the build-up to the Comrades Marathon, including the all-important, how you handle race day nutrition.

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