Lower carb diets and running - Women's Running

Low carb diets and running

Author: Chris Macdonald

Read Time:   |  August 30, 2016

Staying energized, enjoying your runs and losing weight can be a big ask for anyone who enjoys exercise. Low-carbohydrate diets are increasingly popular if you’re looking to lose weight but can they also work for you when you’re running regularly?

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The body prefers to obtain its fuel (sugar) first from easy-to-access stores in your liver and muscle in the form of glycogen. High-intensity exercise will quickly use up these glycogen stores and your body will pump out stress hormones, such as cortisol, to initiate gluconeogenesis – a process of making sugar to provide additional fuel.

When glycogen stores run low, your body is also able to use fat stores as an energy source but the intensity or pace that you’re able to maintain can be affected. This isn’t a problem if you’re tackling a low-intensity workout or gentle run, but may be a concern if you’re looking to maximise performance and speed. Over time, your body can become more efficient at burning fat for energy, which can favour endurance running rather than high-intensity running or sprint work.

Carbohydrates are also important after exercise. Following a workout, your body needs to replenish glycogen stores to speed up your recovery. The more effective your recovery, the better able you are to train the next day, keep energy levels high, repair damaged muscles and tissue, maintain muscle and lose fat.

Many studies demonstrate that lower-carbohydrate eating can help you to lose weight and improve a range of health markers such as blood pressure and belly fat. Low-carb diets are significantly more effective than higher-carbohydrate, lower-fat diets for weight loss. They help control hunger, reduce cravings, stabilise blood sugar and encourage fat burning rather than fat storage.

Low-carb eating for runners

There are many types of low-carb diets and they vary in terms of the amount of carbohydrates recommended. Typically, when you’re following a low-carb diet, carbohydrates make up no more than 40 per cent of your total calorie intake. The actual amounts depend on your goals – this may be weight loss, maintaining a healthy weight or may include improving blood sugar or long-term health conditions.

For runners looking to adopt this type of diet, the best approach is to follow a timed low-carb diet. This means you consume adequate amounts of carbohydrate before, during and immediately after exercise but during the rest of the day you focus on low-carb meals. This would essentially mean high-quality protein foods (meat, fish, eggs, soy, nuts, seeds, protein powders) and vegetables. By following this approach you enable your body to fuel your runs and recover effectively but also improve fat burning during the rest of the day.

Lower-carb eating in practice

The amount of carbohydrate you need will depend on the length and intensity of your workout. Before a run this may mean 20g to 30g of carbohydrates (low-fibre to avoid digestive upsets) and another 50g of carbohydrates during and/or within 20 minutes of finishing exercise. This is clearly more than some of the low-carbohydrate diets, which restrict carbs to around 40g to 50g for the whole day.

In practice, this means that 30 minutes before a run you may snack on some carbohydrates that are easy to digest and absorb quickly. This could include a banana (25g carbohydrate), small box (40g) of raisins (32g carbohydrate), cooked sweet potato (24g carbohydrate), 200g grapes (32g carbohydrate), Trek Bar (38g carbohydrate) or other cereal bar. Energy gels and sports drinks can also be useful options. By timing these carbohydrates appropriately, your body will be burning this glucose to fuel your run rather than storing it as fat.

After your run, you should aim to eat high glycaemic index foods within 20 minutes of completing a workout. For maximum recovery, focus on combining carbohydrates at a ratio of 3g to 4g of carbs to 1g of protein. Using a protein powder with fruit juice can be a quick and easy option or have a bowl of fruit with Greek yogurt and some nuts and seeds.

Chris Macdonald

Editor-at-Large, Women's Running

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