Last weekend, I participated in the Rock-n-Roll New Orleans half marathon. I completed the race in a time of one hour and thirty-nine minutes. It was far from my best race, but a good start to the season after a few weeks of base mileage. Prior to the race, runners attend a Health and Fitness Expo where vendors sell running-related materials such as food, clothing, fitness gear, shoes, etc. One of the publications was put out by the Competitor Group, who is the owner of the Rock-n-Roll Marathon Series.
The magazine included several fitness tips and one of them retold a story of a person attempting to run a half marathon. The person had recently began the Atkins diet. She lost five pounds within two weeks of the race. The well-meaning observer advised the athlete to eat some carbohydrate for energy even though the woman was doing well on her diet. The woman did not want to mess with her dieting success and ignored the advice. She had a bad race due to low energy. The advice, therefore, was to make sure that you train the way you race. In other words, if you were eating carbohydrates during your training, you should continue to eat them through your race. The writer did not make the same advice regarding the low-carb diet, he just left the issue out there. The article was designed to warn others against a low-carb diet period; not just before a race. Instead, they encourage runners to “carb load.” However, they do recognize that there are real benefits to a low carb diet but they don’t think those benefits are consistent with running.
My advice might have been similar. When undertaking carb restriction, one must take into account the time for ketoadaptation. That is, the period where the body adjusts to using ketones as opposed to constant disposing of triglyceride which happens to those who eat the Standard American Diet. This adaptation period can last anywhere from two weeks to two omnths. It truly varies. I would not schedule a race for a couple of months. There are many studies out there on endurance cyclists and runners where they showed that after this period, the athlete can reproduce the same performances (or exceed them). For more on this, and the correct nutrition for athletes, read this piece by Dr. Barry Groves.
Personally, I do not eat prior to a race nor do I drink during the race. I run through all of the water stops. I do drink a bottle or two afterwards but that’s it. I typically eat the night before and stop drinking once I go to bed and I don’t have another drink until after the race. The beauty of this is that I never need to stand in line for porta-potties nor do I have to stop during races. The key is that I train in this manner. Therefore, I see no need to change anything on race day.