Marathon running is a popular activity worldwide, with people of all ages and abilities participating for recreational and competitive reasons. Marathons cover 42.2 km in distance and can take from 4-5 hours for the recreational athlete to just over 2 hours for elite athletes. The current world record for men is 2:03:23, set by Wilson Kipsang, and for women is currently 2:15:25, set by Paula Radcliffe. The demands placed on the body for marathon training and races are significant, and in order to perform optimally, planned consumption of nutritious foods and adequate fluids is essential.

Sport-specific physiological demands

Marathon running is an endurance sport that requires excellent running efficiency, a high level of aerobic fitness, and optimum levels of body fat. The most successful distance runners also have a high maximal oxygen uptake (VO2max). VO2max is defined as the highest rate at which oxygen can be taken in and used by the body during intense exercise. The higher an athlete's VO2max the better their ability is to supply oxygen to working muscles. Top marathon runners can have a VO2max of >80 mL O2/kg of body mass/min, which is an exceptional level of fitness. During a race, energy for performance is derived from carbohydrate (CHO), and to a lesser extent fat circulating in the blood ("fatty acids") and fat stored in muscles ("intramuscular triglyceride"). The CHO used for energy is mainly sourced from muscle glycogen (carbohydrate stored in the muscles), and circulating glucose provided through sports drinks or other suitable sources. Depending on the athlete and the duration of race, a marathon runner may expend as many as 2500 kcal during a race – equivalent to the total energy expenditure over 24 hours of an average adult!

Nutritional considerations

Athletes completing high volume training or preparing for competition must pay close attention to their food and fluid intake. A marathon runner should consume sufficient energy to fuel their training sessions and recover appropriately using a suitable meal plan to facilitate optimum adaptation from their training. Due to the long duration and high intensity of training, there is a significant requirement for high daily CHO intakes. CHO-rich foods are critical for replacing glycogen stores that are depleted during training and competition. However, for general health and in order to optimise body composition (i.e. low % body fat), marathon runners should try to consume the majority of their energy from complex low glycemic index (GI) CHO sources. Athletes should also aim to consume a balanced-diet rich in micronutrients and essential oils to maintain a healthy immune system and avoid illness. An optimum amount of fluid and fuel before, during and after a race is critical for performance. In the lead up to a race, athletes should carbohydrate load to ensure maximum available energy before the race, and carefully plan their fluid and fuel intake during the race to maintain a supply of energy to working muscles. Recovery nutrition should begin immediately with a source of fast digesting CHO and easily digested protein to replace depleted glycogen levels and facilitate the repair of damaged muscles.

The importance of carbohydrate and carbohydrate loading

Highly-trained marathon runners can oxidise 200-250 g of CHO per hour at racing pace. Even if athletes begin the race with maximum glycogen stores, muscle glycogen will be depleted long before the end of the race. Marathon runners are well familiar with the phrase "hitting the wall" - this is an expression used to explain the feelings of fatigue an athlete experiences when he/she has depleted their glycogen reserves towards the end of the race. To help prevent this occurrence, nutrition strategies are employed prior to beginning a race to maximise CHO stores on the day, and then during the race in an effort to spare muscle glycogen stores that in turn can be used later in the race.

Carbohydrate loading is a proven strategy which involves supercompensation of muscle glycogen stores to improve exercise performance. Supercompensation leads to an increase the level of glycogen in their muscles above normal levels to maximise performance. By ensuring that glycogen levels are maximally filled, athletes are more likely to perform to their potential. Athletes should taper training (reduce volume) in the 3-4 days leading up to a race, while simultaneously increasing their daily CHO intake to 7-12 g of CHO per kilogram body mass, equal to 60-70% of total energy intake. The majority of the CHO consumed during this period should be from slow-digesting (low GI) CHO to minimise insulin and blood sugar fluctuations, and liquid sources such as RecoverAce Endurance may be used to facilitate these high intakes.

Fuel and fluid intake during the race

The development of dehydration (mainly through high rates of sweating) is strongly associated with a reduction in race pace. A fluid intake plan personalised based on an individual's estimated or measured sweat rate is ideal, but as a general rule, athletes should aim to consume 150-300 mL of a sports drink every 5 km. This will provide fluid to maintain hydration status and also a source of CHO to maintain energy levels. In fact, consuming an easy-to-digest CHO source is particularly important in the latter stages of the race when glycogen reserves are close to depletion. CHO CHARGE contains an optimum amount of fast-digesting CHO, in the form of Vitargo®, and fructose to provide energy to the muscle – this is based on the latest research showing similar CHO combinations provide greatest ability to rapidly deliver glucose to working muscles. CHO CHARGE is an isotonic sports drink, and also contains electrolytes to aid palatability, offset electrolyte losses in sweat and enhance fluid absorption.

Nutrition for recovery

A well-developed nutrition strategy during the immediate phase of recovery can benefit athletes in a number of ways, including helping to replace depleted glycogen levels, and a quality source of protein will aid muscle tissue repair. The co-ingestion of protein and CHO in optimum amounts is suggested to be the most practical means of maximising recovery and facilitating adaptations from exercise. Recover Ace Strength and Recover Ace Endurance are two recovery formulations based on the latest scientific findings for optimum recovery for either strength- or endurance-based training.

Other nutrition considerations

Extreme exercise such as marathon activity can result in muscle tissue damage, fatigue and immune suppression. Athletes and researchers are always looking for new ways to improve recovery rate. Certain foods and antioxidants have in recent times being credited with an ability to reduce inflammation and muscle soreness resulting from intense exercise. Omniflex is a specially formulated combination of antioxidants and natural anti-inflammatory ingredients that can support recovery from intense exercise.

For more nutrition, training and sports articles, please visit our Nutrition Centre.

ROS Recommends

Goal Why? ROS product
CHO loading Maximise muscle glycogen stores that are critical for performance RecoverAce Endurance
CHO and fluid supply during exercise Offset dehydration and muscle glycogen depletion, key factors contributing to fatigue CHO CHARGE Decaffeinated
Recovery product Restore fuel stores and support optimum muscle recovery RecoverAce Endurance
RecoverAce Strength
Amino acid supplementation Facilitate training adaptations Aid growth and repair ISO BCAA Max 1500 mg
Quality protein intake Essential for maintenance of optimum body composition Blue Label Whey
Target Whey Protein
Calcium Caseinate
Multivitamins and minerals Ensure adequate intake of essential micro nutrients Accovit Performance - Men
Accovit Performance - Women