It's 6 a.m., and the sun isn't up yet. You drag yourself out of bed for an easy 8 kilometres before work. Should you stop to grab some food before you head out? It's always tough to know whether or not running on an empty stomach is a bad thing, and if so, how to fuel in a pinch.
The experts seem to be torn on whether running on an empty stomach could hurt your progress or even enhance it, but one thing is clear: It takes strategizing before hitting the road with a grumbling gut.
Why is eating before a run important?
Registered dietitian and elite-level runner Starla Garcia typically discourages this practice. "I normally don't recommend runners go for a run on an empty stomach due to blood sugar and energy level concerns," Garcia said. "Starting a run fasted can induce hypoglycemia symptoms, make a runner feel sluggish, and can negatively impact their recovery time."
For those who end up in a position where they can't eat before a run, Garcia recommends the following strategy: "If someone is hungry, they should eat prior to the run no matter the time it would take or pace. If someone is running 45 minutes or longer, it is recommended to have a simple carbohydrate snack to help manage blood sugars and energy levels."
She also recommends considering the type of run. For instance, a fartlek or track workout will require more energy if someone is seeking to get faster. "A runner needs energy to stimulate adaptation and to also help them recover faster."
Are there any benefits?
Running coach Casey Coleman is not surprised that there is interest in fasted runs, and he's attempted quite a few himself. "Some runners argue that to truly maximize race-day performance, we should train our bodies to not only rely on our fully stocked glycogen stores, but to improve our body's ability to use fat as a fuel source," he said.
He suggests these types of planned longer depletion runs should only be used sparingly (once a month), and early in a marathon training cycle. "I also recommend carrying gels or having carbs ready in case you feel unduly fatigued or like you are hitting a wall," he added.
Whether you accidentally find yourself running on an empty stomach or you plan them occasionally, post-run fuelling is important. Carbs and protein should be top priority immediately after your runs to refuel and aid in recovery. No matter what, you should also be hydrating and regularly keeping up your glycogen stores, which will keep you from hitting a wall, but also help you reach your goals and enjoy your runs.
Our writer's advice is intended for informational or general educational purposes only. We always encourage you to speak with your physician or healthcare provider before making any adjustments to your running, nutrition, or fitness routines.