Brrr-eakfast of Champions

How to fuel your fitness during the winter months.

The weather outside is frightful, but a workout would be delightful. How should I eat for my cold weather training?

- The Poetic Pedaller of Park City

Thank you for the question, PP!

Here’s a short response:

You don’t need to change your diet that much when the temperature drops—assuming you’re exercising at the same volume. You might burn a few more calories due to thermoregulation—your body’s internal thermostat—but your hunger and satiety hormones should shift to increase your appetite, so it’s probably not worth focusing on.

Here’s a longer (slightly more curmudgeonly) response:

I had to wade through a lot of online garbage to get to this answer. Most of the articles on the topic from otherwise credible sources are vague. For example, an NASM blog post, “Winter Sports and Cold Temperature Nutrition,” offers a fueling strategy that would be more aptly titled “Sports Nutrition 101 Regardless of Weather” featuring boilerplate instruction except for suggesting that you “try warm fluids.”

In other words, much of the advice sounds fancy but ultimately recommends that you eat the same as you did before, only warmer.

There’s also an article floating around titled “Want to burn more calories? Work out in the cold.” By “floating,” I mean that it’s been plagiarized on several sites, so I’m not sure who originally wrote it. I went with the NBC Today Show version, which lists the author as “Contributor.”

The article features a University at Albany study demonstrating that hikers in winter burned more calories than hikers in summer. The provided link to the study is dead. I found it anyway, no thanks to Contributor.

“Human energy expenditure, allocation, and interactions in natural temperate, hot, and cold environments” does show that winter hikers burned, on average, 1550 more calories per day. However, study’s lead author Dr. Cara Ocobock explains on her personal blog an important factor of the research that Contributor missed:

“It is not really the cold (thermoregulatory costs) that make the calorie burn so high, but how difficult it is to move around a snowy, mountainous environment.”

You do burn some extra calories by thermoregulation, but not the giant load the Today Show clickbait suggests, unless you plan on running or cycling through snow. This would be super fun and Instagram-worthy, but probably not what most people do.

A 1996 military field guide, Nutritional Needs In Cold And In High-Altitude Environments, vaguely backs up that increased thermoregulation burns some calories by suggesting, “It is likely that the distribution of requirements will result in the need for some individuals to exceed the (current U.S. Military Recommended Dietary Allowance) for cold environments.”

At least, I think the guide intends to say that. I’m not sure, given it reads like a lost chapter from Catch-22.

A 2011 Journal of Sports Sciences article, “Nutrition for winter sports,” also acknowledges that “work in the cold may increase energy requirements” but goes on to explain that big calorie burns only come when you start shivering.

Just say no to shivering.

When you shiver, your muscles involuntarily contract and relax, generating heat. Just like any other muscle movement, this requires energy. Up to 80 percent of the energy used for shivering can come from glycogen. In extreme conditions, it can oxidize 1.5 grams of carbohydrates per minute. (That’s 360 calories an hour.)

If you plan to deliberately induce shivering as part of your training plan, please don’t. Shivering is a warning sign of hypothermia—and hypothermia-caused mortality in endurance athletes is not uncommon.

If you’re not one to let death get in the way of a solid workout, let’s take another angle. Like I said, shivering burns a lot of glycogen, which is an important fuel source for exercise. As the 2021 paper “Practicing Sport in Cold Environments: Practical Recommendations to Improve Sport Performance and Reduce Negative Health Outcomes” puts it, “In the context of sport, shivering due to inadequate clothing pre competition can reduce glycogen availability, thereby impairing ‘exercise performance.’”

I’m extrapolating, but I think it’s safe to say that this advice goes beyond wearing shorty shorts as you wait at the starting line.

Let the calories take care of themselves.

If you have a burning desire, sure, add a couple hundred calories to your diet plan to allot for thermoregulation. Just keep in mind that people tend to move less during winter in general. When it’s dumping rain or the wind kicks up, you’re less likely to do that extra lap, so your overall total caloric output probably balances out without the added intake.

If you eat ad libitum, meaning that you don’t specifically regulate calories, your gut has you covered. A 2017 review in the journal Nutrients looks at how hunger hormones and satiety hormones are impacted by hot and cold weather workouts. During cold workouts, ghrelin (a hunger-promoting hormone) may go up and leptin (a hunger-decreasing hormone) may go down. This means that you probably unconsciously eat more to make up for any extra thermoregulated burn.

A word regarding water.

Instead, maybe focus on hydration, considering the role hydration plays in thermoregulation. It’s easy to remember to drink when you’re hot, especially when you perspire. But even when your pores aren’t pouring, you lose fluids. You still sweat; it’s just not as obvious. Also, you breathe out water when you exhale—as evidenced by the steam that comes out of your mouth when it’s cold.

Regarding those “warm” fluids the NASM recommends, personally, I think it’s more important to get “any” fluids. However, an interesting 2017 study out of Australia suggests that favoring warm fluids in cold environments won’t increase core temperature faster—but may trigger thermoreceptors in your gut that allow you to maintain “gross motor performance” longer, meaning your ability to walk, run, pedal, ski, or paddle.

So, I begrudgingly admit the NASM has a point about their warm fluids—but that’s partially because it gives me another excuse to drink coffee.