Nutrition

Diet mistakes that all runners are guilty of

Apr 27, 2020

There are a number of mistakes that runners make when it comes to nutrition. What we need to keep in mind is that all diet requirements are individual and must be personalised according to our own goals and ambitions. Dietary requirements for runners will vary largely according to age, gender, training load and stage of training.

running nutrition mistakes

Overtraining and under fuelling

The most common mistake that runners make is trying to maximise weight loss with exercise. Weight loss is often explained using the energy balance equation; energy in versus energy out. Theoretically to achieve weight loss we need to eat less and move more. This is however not always the case. Running requires energy. The body has energy stored in the form of glycogen and can get from food. Intentional not eating to achieve weight loss can cause both positive and negative adaptation. Under fueling places stress on the body, can inhibit training adaptation, slow down recovery, weaken the immune system and actually lead to weight gain or inhibition of weight loss.

Over consuming protein

Protein is more often than not placed in a positive light in the exercise and diet world. Protein is seen as the building blocks in gaining muscle and the most important component in recovery after training sessions. The calorie load of protein is ignored or not well understood. Protein is not free of calories, can be high in fat and, if eaten in excess, will contribute towards weight gain and therefore inhibit weight loss. The general recommendation for very active individuals is 1.2 – 1.4g of protein per kg of body weight. Protein shakes on average offer roughly 27g per serving. For a small, lean runner, this is close to half of your daily protein requirement. Know your requirements.

Eating whatever you like because you’re a runner

Understanding calories is very important. Calories burnt through exercise do not come close to the calories we consume from food. Most runners run with some sort of watch which will give a basic indication of calories burnt during your run. Accuracy of your device, fitness level, heart rate, weight and gender, are just a few factors that need to be considered when analysing your calorie output for the day. The type of exercise you do will impact on your metabolic rate. Calories burnt from running will help create an increase in your metabolic rate around the time of exercise and help in achieving your calorie deficit for that day. This however will need to done consistently to achieve your desired goal.

Sports nutrition versus healthy eating

When it comes to fuelling close to exercise or during exercise, we look for quick release carbohydrate sources which may be refined or high in sugar. This is necessary to provide the body with the fuel it needs. This is just about the only time that runners require sugary, refined carbohydrates and should at every other stage of the day give preference to whole-grain, high fibre, slow release carbohydrates. It is important to avoid refined carbohydrates and limit them to races, longer runs and higher intensity training sessions as they will cause spikes and dips in blood glucose, enhance cravings, impact mood and can negatively affect the immune system and muscle recovery.

Focusing more on running than diet

All runners know that running is in fact a multidisciplinary sport. We need to place just as much emphasis on strength training and good diet as we do on running. Sports nutrition in endurance athletes can be the difference between a mediocre runner and a great athlete. Good nutrition allows for consistency of energy and therefore training, adaptation to training and enhances recovery by providing the body with what it needs. Good nutrition therefore prevents injury and illness and keeps us training and ready to compete.

Jenna Bowes


Jenna is a registered dietitian with a private practice in Bryanston, Johannesburg. She is highly qualified with BSc degrees in Dietetics, Sports Science and Psychology. Jenna is also a keen sportswoman and has competed at the 70.3 World Iron Man Championships. Read more about Jenna Bowes here

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