Neglecting your meals is never a good idea, but for runners it may be getting in the way of good performances and affecting your health.

Running on emptyIs this you? You’re a regular runner but not really a regular eater. Maybe you can’t face breakfast, or you’re so busy during the day that you forget to eat lunch altogether, or you grab a quick snack. You tend to eat most of your food in the evening, so often you are running on an empty stomach. Perhaps you have chosen to run on fewer kilojoules as part of your efforts to lose weight. If this is you, you’re not getting the most from your running, and you may be damaging your health.

Fuel for your fire
When you run, your body burns a mix of glucose and fat for energy. The higher your heart rate, the more glucose (rather than fat) you burn. This is released from the carbohydrate stores (glycogen) in your muscles. The lower your heart rate, the more fuel you produce from your body fat. But even when you are running slowly, your heart rate is likely to be more than 60 percent of your maximum, so glucose remains the major fuel source. Fat becomes the primary fuel source only when your heart rate is below 60 percent of maximum.

If your glycogen stores are empty and you’re depending on fat for fuel, you’ll probably find that you can’t run as far or as fast – it takes longer to convert fat into energy. You may also find it harder to recover. This is why it’s a good idea to have some carbohydrate between 15 minutes and two hours before running, especially if you ate lightly earlier on and want to run in the evening.

Health Care
In 2009, the American College of Sports Nutrition published a paper in the journal Medicine and Science in Sports and Exercise, stating that adequate food and fluid should be consumed before, during and after exercise to maintain blood sugar, maximise performance and improve recovery time. This is good advice. As well as affecting your ability to run well, eating fewer calories – and therefore consuming fewer nutrients than your body needs – may affect your health.

If you combine a diet low in calories and nutrients with a tough exercise programme, such as marathon training, you risk developing “over-training syndrome”, where your performance plateaus or declines, or you may become injured. In some cases, women runners who under-eat for a long time develop the “Female Athlete Triad”: they stop menstruating, have reduced bone-mineral density and develop disordered eating patterns.

The Fast Track

As a rule, you should eat something before running, but some research has shown that people training for endurance events such as marathons may benefit from doing occasional runs in a fasted state to increase their capacity to burn fat as fuel. This is known as “train low, compete high”. But this approach has not been found to deliver performance benefits in a shorter race, such as a 10K, in which you run at a higher intensity and therefore rely on carbohydrates for fuel. It’s not a good idea to do interval training or run for over an hour in a fasted state, and it’s important to eat a recovery meal containing carbs and protein shortly afterwards.

To get the most from your running, make sure you eat enough to support your activity levels. The average woman requires just over 8,000 kilojoules a day; runners may need more, depending on their size and how much they train. Include sources of carbohydrate before and after your runs, and choose unprocessed foods, to increase the amount of nutrients in your diet. In short, watch what you eat, but in a good way.

Putting Pep in Your Step
It’s best to have a meal or snack no earlier than three hours before a run. If you have forgotten to eat something, or want to run shortly after you wake up, take an energy gel just before you head out. These semi-liquid sources of carbohydrate are quickly absorbed and you should notice an effect on your energy levels within 15 minutes. If you find gels hard to tolerate, a good alternative is a glass of fruit juice diluted with water, or 250ml of sports drink with 6-8 per cent carbohydrate content. Some people find they can manage a ripe banana shortly before running.

Words: Jo Scott-Dalgleish