Tag: nutrition

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The magic carbo-loading calculator

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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Okay, I’m a bit late to the party on this one. A couple of weeks ago, the newswires were buzzing with the news of MIT/Harvard MD-PhD student Benjamin Rapoport’s new calculator that allows you to determine exactly how much carbohydrate you need to load up on before running a marathon. Putting aside my initial skepticism (surely how much carb you need to load up on is well known by now?!), I finally had a chance to check out both the calculator and the PLoS Computational Biology paper it’s based on (the full text is freely available at the link).

The quick summary: the calculator is just a toy, and should not guide your fuelling decisions; the paper, on the other hand, I found surprisingly interesting — though I still wouldn’t use it to plan my fuelling strategy. Continue reading “The magic carbo-loading calculator”

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What does a nutritionist do at an international Games?

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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I went to the Delhi 2010 Athletes Village for the first time yesterday (generally lovely, if a little rough around the edges in places), to chat with Jon Kolb, the head of sports science for the Canadian team here, and Trent Stellingwerff, the member of Kolb’s team responsible for nutrition. We had a really interesting talk about the kinds of things they’re up to behind the scenes, which I’ll try to describe in the coming days. To start, here’s a great example of what Trent was doing in the days leading up to the Games.

While the cafeteria at the Village is excellent, many athletes will be too far away when they’re competing to return for lunch. In these cases, it’s standard practice at major Games to order an “athlete venue meal” (AVM) that will be delivered to the venue at a specified time. Given the hot climate and the ever-present risk of “Delhi belly,” Trent decided he’d better check out the AVM system. So, a few days before competition started, he ordered the very first AVM — “AVM 001” — asking that it be delivered at noon to the cycling venue. Then he showed up at the appointed time… and waited.

“It came 30 minutes late, in a warm cooler,” he said. “It was a raw salmon sandwich with mayonnaise — basically the worst possible scenario for food poisoning.” That was enough to convince the team staff. No Canadian athletes are relying on AVMs here — instead, they shipped in some familiar non-perishable food from Canada, and are also bringing easily portable food (e.g. bananas) from the dining hall.

Of course, Trent was left with the dodgy AVM he’d ordered — while the delivery guy, happy to have made his first successful delivery, sat beside him and waited for him to eat it. Trent finally asked for a spoon, and when the delivery guy went to get, he stashed the sandwich in his bag for later disposal!

On the topic of food, here are the first two meals I had in Delhi:

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img_0002In my defence, my flight arrived at 7 a.m., and by the time I got to my hotel and got checked in, I was jet-lagged and furiously hungry. I went wandering down the street in search of food, and the first place I found was a McDonald’s. I haven’t been in one in years, but I’d heard that McDonald’s in India are quite different because of the lack of beef — so I figured it would be a cultural experience! (The verdict: “special sauce” is indeed interesting when it’s spiced up with curry, but I don’t feel any need to sample it again.)

My second meal, thanks to a suggestion from one of the Games volunteers, was a masala dhosa from Saravana Bhavan — much, much better!

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Mission: pickerel

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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I’m heading out in about half an hour for my annual canoe trip, this time on the Lievre River in the Laurentians. My mission: catch at least one delicious pickerel like this one I caught last year on the Noire. (That’s “walleye” for you Americans out there.) Also, try not to add any scars to the big one on my hip that I picked up last year while navigating a 200-metre-long rapids a few metres behind my upside-down canoe. At least this year I’m bringing a helmet! I’ll be back in a week…

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Scott Jurek, the vegan ultrarunner

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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Interesting article in the New York Times about ultramarathoner extraordinaire Scott Jurek, who relies on a vegan diet to get the 5,000 to 8,000 calories per day that he needs. NYT food writer Mark Bittman (a.k.a. The Minimalist) invited Jurek over to cook a (delicious sounding) meal. My favourite paragraph from the piece:

He said he spent a great deal of time shopping, preparing and cooking food — and chewing. He is among the slowest and most deliberate eaters I know, and there is something about his determination at the table that is reminiscent of his determination on the road: he just doesn’t stop.

The article also notes Jurek’s quest to set an American record at the 24-Hour Run world championships in France, which are taking place as I type. According to Jurek’s Twitter account, he seems to have just taken the lead for the first time shortly after the 14-hour mark, from Japan’s Shingo Inoue (who had been on world-record pace through halfway, 5K ahead of Jurek).

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Training without breakfast boosts glycogen stores

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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I posted last month about the “train low, compete high” concept, in which you do a depletion workout to empty your glycogen stores, then do a hard workout while running on empty. The idea is basically the nutritional equivalent of running with a weighted vest — it makes training harder, and perhaps forces your body to adapt to the tougher conditions so that when you do fuel up properly, you get an extra boost. But results so far have been ambiguous: your body does respond in several ways, including learning to burn more fat instead of carbohydrate, but there’s no good evidence that it actually improves performance. And it’s very hard and makes you feel like crap.

A kinder, gentler version of “training low” is doing your workout before breakfast, without restocking the glycogen that you’ve burned overnight (your liver glycogen stores drop by about 50% while you sleep). There have been a few studies on this regime, and the most recent is now in press at the Journal of Science and Medicine in Sport. Researchers in New Zealand had 14 cyclists perform a four-week training program, five mornings a week, starting with 25 minutes per session at 65% of VO2max and building up to 100 minutes per session. Half of them had a “standard cereal breakfast” an hour before working out, while the other half had the same breakfast shortly after working out.

The results were pretty striking. The fasted group increased the amount of glycogen stored in their muscles by 54.7%, while the breakfast group increased by just 2.9%. The fasted group also increased their VO2max by 9.7%, compared to 2.5% in the breakfast group. The other interesting finding is that men and women responded differently to some of the training adaptations: men seemed to benefit more from the fasted training, while women seemed to benefit more from the fed training.

Some caveats: First, it’s a small study, so the margins of error are high. Second, the subjects were untrained — athletes who are already training definitely won’t boost their glycogen stores by 50% or their VO2max by 10%, so it’s possible that the differences may disappear entirely. Third, actual exercise performance wasn’t measured as an experimental outcome. The literature is full of bright ideas that change some parameter in lab tests but don’t actually make you faster when the chips are down. Finally, the training program isn’t one that anyone would implement in the real world. It’s highly unlikely that doing ALL your training in a fasted state is the optimal approach.

Still, the results are interesting. They raise the possibility that mixing in an occasional fasted workout, perhaps once or twice a week, could provide your body with a different sort of stimulus that might prompt some useful adaptations. And this no-breakfast approach seems a lot more realistic to me than the idea of doing a one-hour depletion run before a hard workout.

(Thanks to Steve Magness for pointing out the study.)