If you are an endurance athlete who is fearful of “hitting the wall,” listen up: proper fueling before your marathon can make the difference between agony and ecstasy!

If you plan to compete for longer than 90 minutes, you want to maximize the amount of glycogen stored in your muscles because poorly fueled muscles are associated with needless fatigue. The more glycogen, the more endurance!! Words of Nancy Clark RD (SA)


PHYSIOLOGY 101 – Glycogen: Glycogen is a “chain” of glucose molecules (polysaccharides) that serves as a form of energy storage. Glycogen is made and stored primarily in the cells of the liver and muscles.

Endurance sporting events, such as a Marathon, place large demands on muscle glycogen stores. Your body can only store enough glycogen (in your muscles and liver) to sustain 90 minutes of exercise – after 90 minutes, it gets depleted. If the diet has been inadequate in the lead up to an event it can be depleted even sooner. Once glycogen is depleted, there is insufficient fuel to the muscles and you are in danger of running out of energy and coming up against the dreaded “wall”.

The goal of carbo-loading 2 days before the race is to increase the glycogen storage capacity of your muscles, and hence improve your endurance performance.

Sports drinks and carb gels are great for topping up your energy levels during a long run or race, but increasing your carb intake three days before the race (and most importantly the day before the race) will help make sure you reach the start line with sufficient energy to run at your best.

Loading your muscles with glycogen before you start your race may not make you run any faster, but it will prolong the time you can exercise at your optimum pace.

BUT you don’t need to increase your food volume or kilojoules the day before the race, just replace some fats or proteins with carbohydrates. However, you need to choose your carbohydrates wisely.


After months of training and dedicating yourself, your body and your mind to the 86.96 km ahead of you, the last thing you want to do is mess it all up due to incorrect fuel carbo-loading. By carbo-loading properly (particularly the day before the race) you can potentially finish faster than those who have eaten fewer carbohydrates the day before.

And how do I know this?

A study published in October 2012 1 replicated the results of a study published the year before 2. They both found that runners who loaded up on carbohydrates the day before the race ran faster than those who had eaten fewer carbs. Thus both studies concluded, for both men and women, carbo-loading is best if it is shortened, encompassing a day or so of dietary manipulation. The difference was especially striking beginning at about the 30km mark, just when many runners famously “hit the wall” and feel their energy flag. The carbo-loaded runners jauntily maintained their pace. The others did not.

In both studies, carbohydrates eaten at breakfast on race day, during the race itself or on days earlier in the week were relatively unimportant. It was primarily what people ate on the day before the race that mattered.

And yet, few of the runners in either study actually consumed enough carbohydrates to benefit, even if they thought that they were doing so. In both studies, the minimum effective “dose” of carbohydrates was at least six or seven grams for every kilogram of a person’s body weight.

Leigh-Ann’s suggestion: Carbo-load two days before the race, and in place of eating one or two carbo-loaded meals, rather graze on high carbohydrate foods in 3 meals and 2-3 snacks during the day. Although the current research shows that what you eat the day before the race is critical, interviews with marathon runners and exercise physiologists demonstrate that increasing carbohydrate intake 2-3 days before the race also helps increase glycogen stores.


Leigh-Ann suggests that runners choose concentrated sources of carbohydrates such as potatoes. That way, the volume of food needed isn’t so enormous. In addition, you may need to decrease the fibre content of the meal the day before and on the day to reduce potential stomach distress during the race. Potatoes help increase or decrease fibre content depending on the cooking preparation and method. The best way to cook and eat a potato is baked/boiled/steamed in the jacket. However, if you need to reduce the fiber content then you can prepare and eat it without the jacket. A delicious, quick and easy idea is to cut peeled potatoes into wedges, drizzle with oil and sprinkle with salt. Roast/bake in the oven until crispy.

Leigh-Ann’s recommendation: Do not completely upend your normal diet. Stick with familiar foods and don’t experiment with new foods just before the race.



Leigh-Ann’s advice: Do not make the mistake of eating one massive meal full of carbohydrates, only to feel full, lethargic and uncomfortable thereafter. Spread your carbohydrate intake evenly throughout the day. Sensible carbo-loading is about breakfast, lunch, dinner and 2-3 snacks, with each meal containing carbohydrates as the main food component.

SUGGESTION: Make lunch your biggest meal of the day. That way you won’t feel uncomfortable at night.

Carbo-loading with the best – Potato power


Leigh-Ann loves to remind her fellow runners that potatoes are full of key nutrients that can help boost running power.

Sports scientists have found that potatoes are an ideal source and that carbo-loading with potatoes can influence peak performance3. This emerged in a study conducted by the Sports Science Institute of South Africa (SSISA), in which eight athletes carbo-loaded with potatoes before a three-hour exercise trial.

Potatoes not only have value prior to endurance events, as well as when the sportsperson is in recovery, but also during the event itself.

One medium sized potato (150g), cooked with skin, is high in carbohydrates, naturally free of fat and naturally very low in sodium. It is high in the mineral chromium. In addition, it has a potassium content that is higher than most other vegetables and starchy foods.

Next time you carbo-load, grab a potato and see if you feel a difference in your next long run.

Remember, as so aptly put by Dan Gable: ‘Gold medals aren’t really made of gold. They’re made of sweat, determination, and a hard-to-find alloy called guts.’

You can’t alter your training or talent the night before a big race, however you can have a steaming baked potato and call it race preparedness.


1. Wilson PB, Ingraham SJ, Lundstrom C & Rhodes G. Dietary tendencies as predictors of marathon time in novice marathoners. Int J Sport Nutr Exercise Metab. October 2012.
2. Atkinson G, Taylor CE, Morgan N, Ormond LR & Wallis GA. Pre-Race dietary carbohydrate intake can independently influence sub-elite marathon running performance. Int J Sports Med. 2011. Aug;32(8):611-7.
3.Laurie HG, Rodger I, Wilson R et al. The Effects of Carbohydrate Loading on Muscle Glycogen Content and Cycling Performance. Int J Sports Nutr. 1995 (5): 25-36.

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