If you’re trying to lose weight alongside running, you might also be following a low-carbohydrate diet. And, given the popularity of such diets and the bad press carbs seem to get as a result, it’s easy to understand why. But when put under the microscope, and into context, much of what we hear about carbohydrates and weight gain is unfounded. “The reason why carbohydrates get bad press is because if you look at the average person, before they’ve had normal intervention, they’re probably consuming 350g of carbohydrates a day, without thinking about it,” explains performance and clinical dietician Renee McGregor. “If they’re then not being physically active, consuming any excess calories will help them be overweight.
“One massive misconception people have is that it’s only carbohydrates that trigger an insulin release. Every time you eat, it triggers an insulin release, whether that’s protein, whether that’s fat, whether that’s carbohydrates. They’re just different levels. You don’t trigger fat storage just because you’re eating carbs.”
One of three macronutrients found in food, alongside fat and protein, carbohydrates play a crucial role in our diets. Broken down into glucose and absorbed into the bloodstream, carbs are our body’s primary energy source. Glucose – in the form of glycogen – is found in the liver and muscles and, if it’s consumed in excess, is converted to fat for long-term energy storage.
Glucose is not just used as energy to fuel physical activity but all our bodily functions, too. “Your brain needs 120g of glucose a day just to function – just to keep all of the processes in the body going,” explains McGregor. “If you reduce your carb intake too low, particularly for females, it has a massive impact on your oestrogen levels, which can then have a massive impact on cholesterol levels and bone health. I’ve seen this in runners, triathletes and even recreational gym users, who, when they cut carbs out, then don’t menstruate”.
Given carbohydrates are the body’s primary energy source, for runners, they are essential pre- and post-run fuel. “If you don’t have your energy in your system, you can’t hit those paces,” explains McGregor. “If I’ve not eaten well the day before – even [before] a run at an easy pace – then I really struggle. It takes 24 to 48 hours for carbohydrate to be turned into glycogen stores, so there’s no point in eating a bowl of porridge that morning, having had no carbs the night before and thinking you’re going to perform optimally. Because you’re not.”
McGregor points out that your diet – and your carbohydrate intake – should be dependent on your training goals. Runners with a high weekly training volume will have a greater demand for carbohydrates in their diets, given their high energy output. “Fuelling your body correctly will mean you benefit from your training, but it depends on what you’re training for,” she says. “If you’re running because you enjoy it and just want to do it three times a week, then having a slightly lower intake of carbohydrates every day is not a bad thing, but I would never cut it out. I recommend people take on a fist-sized portion at most meals and, if you’re doing a bit more, you might introduce some carb-based snacks. If you have