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  • Writer's pictureAnnie Bothma


Updated: Feb 2, 2023

By Annie Bothma, 10 October 2022

Everyone know the number one rule before a marathon is:


The hard work is done and there is no fitness left to be gained before race day. You can do more harm than good by doing too much in the final two weeks before a marathon or panicking and suddenly doing something you have never done before. Now is not the time to make any big changes to your diet either. The last few days leading into the race don't drastically reduce or increase your intake or try out some fad diet you think may give you the extra edge on race day - it won't! Just like you won't suddenly go buy new shoes and only test them out on race day, you should not experiment with new nutrition products or unfamiliar foods before or on race day.


There is evidence that higher than normal pre-exercise muscle glycogen contents increase the time to exhaustion and performance in time trials lasting over 90 minutes in duration. This means higher glycogen concentrations in the muscle results in less fatigue and better performance! Since the late 1960s, several carbohydrate-loading regimens have been developed to enable athletes to store supra-normal amounts of muscle glycogen.


The traditional approach was a depletion phase followed by a super-compensation in the final few days before the race. This protocol involved an extremely hard workout 7 days before the race, followed by carbohydrate restriction for 3 days. This protocol has many negative advantages, since it may not be ideal to have such a hard workout 7 days before the race and without carbohydrate adequate intake recovery will be compromised. Many athletes also complain of mood changes such as increase irritability, brain fog and poor sleep. A diet that is high in fat with very little or almost no carbs in those 3 days after the glycogen depleting training session may also increase gastro-intestinal problems in many runners. As part of the protocol runners were recommended to not do any exercise the week before the race (which for most athletes is a greater punishment than this extreme diet itself!)

Conclusion, even if this protocol was highly effective, all these negative side-effects may outweigh the benefits.

This extreme protocol is not necessary if you want to carbo-load. Very high muscle glycogen levels can be achieved by just eating more carbohydrates in the last 1-2 days leading into the race. Studies in the 1990s showed that very well trained athletes could achieve similar muscle glycogen concentrations with just 1 or 2 days of carbohydrate loading and reduced training on those days. If you are less trained it may take a little longer to fully saturate muscle glycogen stores.


Most athletes don't realize just how much you actually need to eat to truly carbo-load or super compensate your muscles with glycogen. We can store around 300-600g of glycogen in our muscles, depending on the size and training status of the individual. But to achieve fully saturated muscle glycogen strokes you have to be willing to eat carbs all day long those last those day before the gun goes off!

The recommended amount of carbohydrate intake in the final 1-2 days before the race is 10-12g of CHO/kg of body weight.

Example: For a 70kg runner this means 700g-840g of Carbohydrates!

70kg x 10g = 700g or 70kg x 12g = 840g

If one banana equals 25g of carbs...that is how many bananas!!?

Now you understand that it is not as easy as it looks and you have to be willing to eat quite a lot of carbohydrates. But don't stress, it can be definitely done! Plus the payoff may be worth it if you get that shiny new PB! However, you have to be strategic and smart about your food choices. Stick to foods that will give you the most bang for your buck without making you feel uncomfortable! Because eating more carbohydrates does not mean overeating or eating as much as possible! In fact, when increasing carbohydrate intake it means you have to decrease your intake of other macronutrients coming from fat and protein.


  • Think pasta, white rice, potatoes, white bread, sports drinks, honey, jam, jelly sweets, energy bars low-fiber cereal, etc.

  • For these 1-2 days it is okay to not eat super healthy and consume whole grain products.

  • You want food choices with a high GI (glycemic index) that will promote maximal muscle glycogen storage.

  • Split your carbohydrate intake between main meals (breakfast, lunch and dinner), and add snacks in-between as well as carbohydrate containing fluids like sports drinks which will also give you some electrolytes.

  • Rather have the last large meal at lunch time the day before and to have a lighter meal in the evening. So you don't wake up the next day feeling uncomfortable and full. You need to be able to replenish liver glycogen after the overnight fast with some breakfast.

  • Practice your pre-race meals before hard workouts and long runs, so you know what works well.

Remember - Just like your race nutrition plan this is also something you should practice in the weeks before or when you have a smaller race coming up. If you have not tried it yet, rather stick to what you have done!

Note that every gram of carbohydrate is stored with approximately 3-4 g of water, which means that storage of 500g of carbohydrate is accompanied by an increase in body mass of approximately 2 kg. So, it is completely normal if you gain some weight before the marathon. It is only water! Don't even get on the scale.


The amount of liquids you need to consume will vary greatly based on your individual fluid requirements and sweat rate, however, the aim should be to avoid dehydration and over-hydrating. A good indicator that you’re well hydrated is if your urine is pale yellow in color. Electrolyte drinks are better options than plain water, since they contain sodium which will help increase fluid retention. Consume drinks such as juices, smoothies, flavored milk and sports drinks that contain carbohydrates, since these help meet carbohydrate loading goals. Both solid and liquid carbohydrate sources have the same effects on glycogen storage.


The main goal of your pre-race meal is to replenish liver glycogen stores, which will be depleted after an overnight fast, and top off muscle glycogen. This meal should predominantly consists of carbohydrate. By keeping fats and fibers to a minimum in your pre-race breakfast can reduce the risk of gastrointestinal issues during the marathon. Stick to the pre-race breakfast you have had before your long runs and hard workouts.

The recommended intake in the last 1-4 hours before exercise is 1–4g of carbohydrate/kg of body weight.


The ingestion of carbohydrate in the last hour before exercise results in a large rise in plasma glucose and insulin. With the onset of exercise, however, a rapid fall in blood glucose occurs. This phenomenon is called rebound or reactive hypoglycemia. This does not happen to all individuals, and does not seem to have negative performance effects, but it may make you feel really bad. But there are those individuals who may be more prone to this problem; therefore, it is recommended to determine your individual response based on your experience with various pre-exercise carbohydrate ingestion protocols.


  • Adjust the timing of intake by eating your meal/snack earlier in advance than 30-60 minutes from the start.

  • Combine carbohydrates with other macronutrients like a very small amount of protein or fat. For example a banana topped with a spoon of peanut butter.

  • It can also be completely prevented when carbohydrate is taken 5 minutes before exercise or during a warm-up. This is because there is not enough time for insulin to increase significantly, so the insulin concentrations are still low at the onset of exercise.

  • A key thing to remember as well is when carbohydrate is ingested during prolonged exercise, the potential negative effects of the pre-exercise carbohydrate feedings are reduced.


  • Fatty foods: This adds excess calories and increase satiety

  • High-fiber foods: Will increase satiety and may lead to gastrointestinal distress.

  • Excess protein: Will increased satiety and may compromise carbohydrate intake.

  • Spicy foods or chili may increase gastrointestinal problems.

  • Alcohol: Excess calories, may dehydrate you leading into the race.

  • Too much caffeinated beverages: a high intake could lead to anxiety and increase those pre-race jitters.



  • Avoid anything new to minimize the risk of gastrointestinal distress.

  • Increase your carbohydrate intake in the 1-2 days before the race.

  • The recommended amount of carbohydrate intake in the final 1-2 days before the race is 10-12g of CHO/kg of body weight if you are following a carbo-loading protocol.

  • Practice your pre-race meals before hard workouts and long runs, so you know what works well.

  • Completely prevent rebound/reactive hypoglycemia by ingesting carbohydrates during the last 5 minutes before exercise or during a warm-up.

  • Reduce your intake of fiber, fat, protein and avoid alcohol or any spicy foods in those final two days before your race.

Even if you can't gain any more fitness in those final few days before your race you can still reap the benefits from good nutrition practices right up to the start of the gun. By following these guidelines to fuel and hydrate adequately before you toe the line, you set yourself up for peak performance! So grab that spoon and eat some pasta! #carboloading


  • Sport Nutrition, Third Edition. (2019) by Asker Jeukendrup, Micheal Gleeson

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