Often taken for granted, diet in the weeks before marathon is a very important part of success. Training and nutrition are two of the most important factors determining your performance on a race day. One thing every runner knows, is fuel well before your main workout and make sure to feed your body with nutrient-dense calories immediately after hard runs. But marathon is an extreme challenge and even many professional runners slow down dramatically after covering two thirds of the distance.The most common cause of hitting this wall is muscle glycogen depletion.


With the advent of the muscle biopsy needle in the 1960s, it was determined that the major source of carbohydrate during exercise was the muscle glycogen stores. Glycogen, stored in the muscles and liver, is readily converted to glucose to be used as an immediate energy source during vigorous or continuous exercise. After glycogen stores have been depleted and before gluconeogenesis (the liver will begin to break down fat and protein to form glucose, which can then be used for energy) kicks in, it is not uncommon to see athletes collapse from the extreme fatigue. 


Marathon is fundamentally a metabolic challenge. Pacing and training are important, but so is maintaining an appropriate nutrition plan throughout your training process. Find the foods that you enjoy and meet your training and nutritional needs, and stick with them. 

1. Weight management


To reach racing weight, runners have to eat carefully to avoid becoming overweight. When training for a marathon, fuelling with high-quality foods is necessary to reach the starting line lighter. Muscles burn less glycogen at goal pace, meaning you’re less likely to deprive. However, be careful not to deplete your muscles with a diet. Some studies have confirmed that runners aren’t able to train as hard on a low-carb diet because it produces chronically low glycogen stores. On the high-carb diet, performance and energy levels were maintained.The amount of carbohydrate a runner needs depends on the amount of training. Studies seem to suggest that athletes should target 30 to 60 grams of carbs per hour.

Choose healthy whole foods and eat plenty. Consume sweets and alcohol in moderation. Great choices are whole grain products, pulses, vegetables, fruits, healthy fats like avocados, nuts, seeds, coconut oil, olive oil. 

2. Two weeks before the race


High-fat, low-carb. Research has shown that a short-term high-fat diet could actually do some good. Increase your muscles’ fat-burning capacity with 10 days of fat-loading prior to the race, leaving the last 3 days for the carbo load to ensure your muscles also have plenty of glycogen available. You’ll have to get 65 percent of your calories from fat every day for ten days starting two weeks before your race. It’s not recommended though, that runners use such a diet as their normal training diet. 

Healthy fat loading foods are avocadoes, greek yogurt, cheese, eggs, nuts, olives and olive oil, salmon, and whole milk. Swithch to high-carb diet 3 days before the race and try to get 70% of your calories from sweet potatoes, pasta, white potatoes, whole grains including oatmeal, rice, quinoa, etc.

3. Five days before


You should not experiment with any new foods or venture too far from your normal diet now. If you haven’t tried it before, don’t be tempted. Some runners have very weak stomachs and need up to three hours to digest food before they can run comfortably. It is important to take this information into account when you plan for the race morning. Your last two long runs or difficult marathon paced workouts should be similar to race simulations. Experiment with your pre-race meal before race day. 

Eat the same pre-race meal you’re planning for the night before the race and the same breakfast you plan on having on the race day to give you time to change things up before race day if you find it doesn’t work for you.

4. 72-48 hours before


Begin to increase your total carbohydrate intake by adding in more pastas and starches. Prerun meals are crucial. For the two to three days before your race, choose high-carb, moderate-protein, and low-fat and fiber options. Very high muscle glycogen levels can be achieved by just eating more carbohydrates. 

5. 24 hours before


Ideally, you won’t be too active on the day before the race, so you shouldn’t try to stuff yourself. Eat normal balanced meals like you would normally do on any training day. Make sure you drink plenty of liquids all day long. If you frequently suffer from gastro-intestinal problems, reduce your fiber intake to a minimum the day before the race. 

Avoid high fiber, high fat and high protein foods. Drink enough fluid and check that your urine color is light. It is a good idea to have the last large meal at lunch time the day before and to have a lighter meal in the evening. 

6. Race day


Small breakfast with plenty of time to start digestion before the run. It is important to eat a carbohydrate rich breakfast. The best timing is probably 3 to 4 hours before the start. At this point, you should have a good idea of what works best for you pre hard or long run, so stick with what works.

Try waffles with syrup, a couple of energy bars, a small bowl or rice, oatmeal with banana, bagel with peanut butter, toast with honey, and coffee.

7. 1 hour before
Start your race fueling  5-15 min before the start.  Use sports drinks, gels, chews, bars, depending on your personal preference. 

Tip: In order to dilute the high sugar content in gels, chews, bars, etc, chase with a few sips of water.  

8. During the marathon


Don’t overdrink, don’t underdrink. Try to match your sweat loss alternating water and sports drink at each fluid stop, drinking to meet your thirst but not more. 

Tip: Try taking gels when you’re approaching a water stop and consume it slowly, over the course of a few minutes.



Liina Kurs

A multipotentialite with many superpowers like holistic healthcare, nutrition, professional cooking, photography, natural bulding materials, environment protection, gardening, arts, travelling the world, I embrace and teach spiritual practice, excercise, food and mind connection, importance of healthy and nurturing relationships, virtues of wisdom and openmindedness. I encourage simple and natural living. I also create functional skin care that embraces sustainable wellness.