What Most People Forget About the Pre-Marathon Taper: Secrets to Carb Loading Like a Pro

My friend Ashley is flying to the states from her new home in Switzerland to run the Hartford Marathon on Saturday with me (well, not running together, but you’d better believe we’re going to be drinking pumpkin beer together after to celebrate!). In preparation, she wrote a great post of last minute tips while going through taper, and I thought that was such a great idea to lay it all out there. Taper can be a really tricky and frustrating time, particularly if you’re been giving training everything you have. For example, I know that Laura was going stir-crazy while tapering for Wineglass Marathon this weekend – though she recovered by writing about how her love of football can help her to taper. (And it worked – way to crush your PR, Laura!)

I have never been big on tapering – I much prefer to just run lots of races rather than gear up for any one specifically. That said, I’ve learned the basics of tapering over the years – taper two weeks between your longest run and your race day, and cut back 1/3 of the mileage each week. But the part that most runners mess up is a critical component of tapering: the pre-race carb load. Planning your nutrition carefully is at least half the battle, and it pays to do it properly.

First of all, if the race you’re running will take you 90 minutes or less to complete, you don’t need to carb load at all, since your body won’t run low on glycogen in that time. This isn’t to say that 5Ks are for wusses (quite the opposite, and I should know since I totally suck at short distance all-out efforts), but they just don’t require the extra glycogen stores that a half or full marathon necessitates.

To properly carb load, you need to first deplete your muscles of extra glycogen, eating low-carb/high-fat from five days before until three days before the race. That day (Thursday for a Sunday marathon), you should eat low-carb/high-fat but also do an intense workout to basically demolish any remaining glycogen stores. The reasoning behind this is that when glycogen stores are fully depleted, the muscles are temporarily able to store even more glycogen than they otherwise would. To minimize muscle damage while still depleting the glycogen stores, do something short and intense (perhaps 4 minutes of tabata intervals?) rather than a long run or any kind of weight lifting. Meanwhile, remember that low-carb also means low alcohol… so perhaps this is a good chance to also get some extra sleep instead of carousing till the wee hours? 😉

Two days before the event (Friday for a Sunday marathon), cease high-intensity exercise (though something more mellow like yoga or an easy jog is fine if you’re going stir crazy) and start loading up on carbs. The part that people mess up here is that loading doesn’t mean increasing your caloric intake! That’s a surefire route to bloating (and eventual weight gain if you do this frequently, though for most people a few days won’t mak ea big difference). Instead, change your macronutrient ratios (protein/fat/carbs) so you’re getting a high percentage of your calories from carbs and a low percentage from fat/protein. What does that look like in practice? Well, instead of having a plate that’s 1/4 meat, 1/4 starch, and 1/2 veggies, maybe try 3/4 starch and 1/4 meat or veggies. Instead of an omelet for breakfast, choose oatmeal or toast. Your plate doesn’t need to get bigger, but the portion of space allocated to high carb foods does.

Finally, make sure that you practice carb-loading before race day (perhaps in the two weeks leading up to a long run or B-goal race) to know what works for you. Some people are very sensitive to fat/dairy, and they may want to stick with something blander the night before the race. My friend Morgan swears by eating half a loaf of bread as her pre-marathon meal! My own stomach goes back and forth – sometimes I swear it’s made of iron and I can even have Indian food the night before the race, but other times (when I’ve been running marathons more infrequently), I need to stick to the semi-basics, like pasta with plain marinara sauce. The good news is, even if you have a sensitive stomach, most GI issues clear up within 24 hours – so you can go hog wild on Friday and then stick to the less fun stuff on Saturday 🙂 Happy carbing!

If you’d like to learn more about the science behind carb loading, I wrote a complete and fully sourced article on carb loading for Greatist that may be helpful.