Dream Runners who take advantage of the opportunity to meet one-on-one with Dietitian Abby Chan are often told they need to consume a lot more carbohydrate before and especially during runs. Abby knows a lot more than I do about nutrition, but I know enough to know she’s right.
The two excuses I hear most often from runners for not taking in much carbohydrate during training runs are “I don’t feel like I need it” and “It messes up my stomach.” My answer to the first excuse is that there’s a difference between needing carbs and benefitting from them. I don’t feel I need caffeine to run a marathon, but I use caffeine in marathons because the science says I benefit from it. With carbs it’s the same. You might not feel the 3-4 percent performance benefit you get from consuming them at recommended levels, but it’s there. And as for stomach discomfort, that’s another reason to ingest carbs in training, not a reason to avoid them. Research has shown that the runners least likely to experience GI distress in races are those who practice most with carbs in training.
Another reason to take in carbohydrate during training runs is that it aids recovery. This was shown in a new study led by Italian cardiologist Stefano Righetti. Twenty-nine runners completed a pair of 15-km runs at 90 percent of VO2max. During one of the runs, the subjects consumed carbohydrate at a rate of 80 grams per hour, while the other run was fueled with a zero-calorie placebo whose flavor and consistency matched that of Carbo Gel, which was the product used in the first run.
Inflammatory markers were measured before, during, and up to 24 hours after both runs and were found to be significantly reduced in the carbohydrate condition. The authors concluded, “Adequate carbohydrate supplementation may acutely mitigate inflammation during a one-hour endurance activity of moderate-to-high intensity. These effects could be beneficial for athletes engaging in frequent, high-intensity activities.”
Our takeaway from this study should not be that we all need to guzzle carbs in every single workout. Physiology is complex, and there’s a lot going on besides inflammation, which itself is not a bad thing. Training without fueling now and then fosters metabolic flexibility, enabling your muscles to burn fat as well as they do carbohydrate, and the inflammatory response that follows glycogen depletion helps boost fitness. But it seems likely that by taking in plenty of carbs during most of your harder workouts you’ll absorb higher training loads more effectively while also performing better and getting more comfortable with fueling on the run.