Bonking Twenty Feet from Your Fridge

A new study shows most indoor cyclists don't fuel their rides—or races—properly.

The Upshot, Upfront:

• When it comes to fueling, treat your indoor workouts the same way you treat your outdoor workouts.

• On occasion, it’s okay to eat that donut or cookie or whatever.

My cycling posse recently started what will soon become a time-honored tradition. Every Friday, we meet at Stupid-Hour-to-Wake-Up o’clock and ride to a random, Yelp-approved donut shop in Los Angeles for pastries and coffee. After that, we find the closest needlessly steep hill and plow up it, praying the donuts will not repeat on us. We call it The Donut Seeking Ride (DSR).

As an exercise nutrition expert, should I be bragging about the DSR? Probably not, but as John Steinbeck famously wrote in his acclaimed nutrition treatise, The Grapes of Wrath, “A man got to eat a donut when he got to eat a donut.”

Or something like that.

Besides, a donut’ll set you back about 200-300 calories, which is right in line with the CLIF Bar or multiple gels that most cyclist shove into their jersey pockets for a 50-mile, occasionally intense ride like the DSR.

Which brings me to my point. Most cyclists understand the benefits of fueling with carbs on longer rides. Sure, we might skip the feed if we’re trying to train our bodies to utilize fat stores more efficiently, but we always have something stashed, just in case.

But indoor cyclists? Not so much. A new cross-sectional study in the British Journal of Nutrition suggests that indoor cyclists tend not to meet sufficient carbohydrate needs before, during, and after saddle-time. This oversight occurs during both training and racing, regardless of athlete level.

It totally makes sense. One of the appeals of platforms like Zwift is the ability to hop on your bike and get a legit workout without the 28-point checklist required for an outdoor excursion, including packing fuel. Hell, you don’t even have to wear pants in Watopia. (I’ve experimented with this and strongly advise against it.)

But the findings aren’t that dire, considering the study didn’t look at overall diet—just pre/during/post effort feeding. This matters because, if you have a reasonably healthy diet, you should have the glycogen stores for any sub-hour effort, which is the norm for most indoor rides.

Fueling becomes more important with rides that go past 90 minutes—but even riders doing two-hour-plus efforts failed to eat enough. Even this might be okay (sort of) since training with reduced carbs (“training low”) occasionally has been shown to improve endurance performance.

The part I don’t get is the riders who didn’t fuel properly before races. I know I just said you generally don’t need to fuel for shorter efforts, but note the conditional. When it comes to racing, there’s no point in taking chances with your nutrition! What’s more, pre-race feeding is a much tastier speed/power insurance plan than weight doping, from both a culinary and ethical perspective.

What should your pre-race feeding strategy be? Recently, the Supersapiens blog recommended either a solid, balanced meal four hours before the race or a smaller, carby snack within 20 minutes of start. This varies slightly from standard recommendations, but their logic, based on readings from the Abbott Libre Sense Glucose Sport Biosensors their athletes use, is pretty compelling. The gist is that these two strategies will assure a steadier during-race blood sugar level because you won’t approach the starting line in the middle of a blood sugar dip.

And if you want to celebrate your victory with a post-race donut, I won’t get in your way.

P.S. Thanks to The Zommuniqué for turning me on to this study.

P.P.S. Any thoughts on this article? Please comment! And send it to your friends! And your kids—because that’s what kids love, getting forwarded emails from their parents on supposedly “interesting” topics!