This month we asked Sports Nutritionist Vic Johnson to gives us the lowdown on how to fuel when the temperatures drop. So get cozy and read on for some great advice for your upcoming winter adventures.
You know the feeling. The alarm goes off at 5:30am, so you roll over and check the weather app. 21F with snow and wind. Damn! Do you get up and hit the trails like you had planned, or do you hit snooze and curl back up in those warm blankets? Either way, I won’t judge you (your training partner shivering at the trailhead might though). Wintry weather can certainly make trail running more challenging, especially if you live at higher elevations. You’ve got to pick the right trail to run, go through that awkward period of figuring out the right layers to wear (tip: always start colder than you want to – you’ll heat right up!), use different and more gear, and battle the soul-sucking dark and cold. One thing that endurance athletes really struggle with when temps drop is fueling and hydration.
Figuring out the whens, whats, and how much of eating and drinking surrounding your runs is hard enough as is…add cold weather to the mix and it gets even more complex! From teeth-breaking frozen Clif bars to understanding your metabolism in cold weather, let’s go over a few topics and cover the basics for fueling your runs and workouts in the cold correctly. (The TL;DR version: in the cold, eat more carbs than usual, and hydrate even though you don’t feel like it.)
The first thing to think about when it comes to nutrition as an endurance athlete is your day to day nutrition. Are you eating enough? Are you getting the right amounts of carbs, protein, and fat? How about your micronutrients? Have you done baseline blood testing? These are all things that I help my 1:1 athletes understand and dial in. Once those have been addressed, we can start focusing more on the sexy side of sports nutrition: how to fuel your workouts.
During a run, you have three main energy sources: Body fat, glycogen (stored carbs), and exogenous carbs (gels, Skratch, potatoes, etc.). When you eat before a run, what you’re trying to do is store more of that glycogen. So focusing on carbohydrate-rich foods like potatoes, rice, bread, fruit, and even sugary drinks (gasp!) is your best bet.
The longer your run, or if it’s going to be very high intensity, the more carbs you should try to store beforehand. For races, you might even start carb-loading 48 hrs out from the start. For an easy morning run, you can probably get away without eating before, assuming you already have glycogen stored from dinner the night before. Just in case, it’s never a bad idea to have at least something with carbs before you head out the door, even a bit of applesauce goes a long way.
When it’s cold, you will usually use up those glycogen stores faster, so dialing in this pre-run fueling is crucial (I guess unless you enjoy bonking).
A marathoner usually burns through their glycogen in about 2 hrs or less of hard running. In the cold, that gas tank will become empty even sooner. As a trail or ultrarunner, we don’t want you getting anywhere near running on empty. Which is why I often tell my athletes, start fueling early and often during your run.
Deciding how much to eat during your workout or run depends on the duration, intensity, and how well you have trained your gut to handle carbs while running. The general suggestions are anywhere from 30 grams to 90 grams of carbs per hr of running. When the temperature drops and you’re shivering, you could probably benefit from more than your norm. That means if you’re used to throwing down two gels per hr (~45g), consider adding a third if it’s extra cold for a total of about 65g of carbs per hr.
Yes, you’re also using body fat as fuel, especially at lower intensities, but it’s still really important to keep a steady stream of carbs going in, particularly in runs lasting longer than an hour. Make sure that your fuel is accessible and edible in the cold. Fumbling with gloves and zippers or rock-hard clif bars isn’t going to be conducive to easy fueling. If your gel or stroop waffle is at the bottom of your pack, or zipped up under three jackets YOU’RE NOT GOING TO EAT IT. Practice with different fuels that can handle cold temps, that are easy to access (it’s all about the Naked brand waist belt people! – look it up), and are appealing to eat.
Hydration and Electrolyte Considerations
Yes, I know you don’t FEEL like drinking when it’s cold out. But you gotta, and here’s why. You may not be sweating as much as on a hot summer day, but you are still losing fluid through sweat, breathing, and urine. Especially urine. Have you ever noticed that you have to pee more often in the cold? And no, it’s not because your bladder has shrunk because of the cold (although other things down there may have). It’s because when it’s really cold, blood flow gets diverted from your skin to your main organs, including the kidneys, which leads to more frequent urination. Don’t assume just because you’re peeing more that you’re over-hydrated. It’s inconvenient, but just plan to keep hitting your hydration intake goals and take more pee breaks.
How much you should be drinking depends again on a variety of factors. For most of my ultrarunners, I suggest they drink no less than 500ml of fluid per hr during activities lasting longer than an hour. But the safest thing to do is multiple sweat rate tests, which is something you can do at home. This will give you a more accurate idea of how much fluid you’re losing in sweat and urine, and how to compensate for it. In general, drinking to thirst can work well too, unless you’re bad at listening to thirst cues (and a lot of people are).
Picking a hydration system that works in the cold can be tricky. Some things that are helpful are insulated soft flasks, insulated bladders/hoses, filling up a handheld with hot cider or sports drink, or wearing one layer on top of your vest to keep the flasks from freezing. Adding carbs and or electrolytes to a water can also lower its freezing point very slightly.
Speaking of electrolytes, STOP STRESSING ABOUT THEM. In general, if you are eating a balanced diet, your body is going to store plenty of sodium, potassium, magnesium, etc. to use during runs. Yes, even enough to replace the electrolytes lost through sweat. My advice is to care more about electrolytes when your activity starts pushing 3-4 hrs in duration. Then, as an insurance policy, you might aim for 300-600mg of sodium per hr. But for the shorter stuff, don’t sweat it! (get it?!)
Vic Johnson is a sports nutritionist for outdoor athletes. He does one-on-one coaching with recreational and pro athletes from around the world, focusing mostly on trail runners, cyclists, triathletes, skiers, climbers, and mountaineers helping them know when, what, and how to eat for optimal performance and health. He has degrees in psychology, public health, and dietetics from Brigham Young University and Northern Arizona University. Vic got his start as a nutrition coach working closely with the student athletes at NAU, helping them know how to fuel and also conducting sports nutrition research. He works with clients with varying needs and preferences, but specializes in plant based nutrition for athletes. One reason why he is able to help athletes be so successful with their fueling and nutrition is because Vic is an accomplished endurance athlete himself. He’s competed for years at a high level in trail and ultra running, mountain biking, and triathlons. To Vic, nutrition is the thing that’s missing from the equation for so many athletes, and it’s his mission to help them gain the understanding, skills, and confidence to take their performance to the next level.
He is also co-hosting a trail running and sports nutrition retreat with Trails and Roots in Chamonix, France from July 8-13, 2024. The retreat will include 6 days in a luxury chalet, equipped with its own hot tub & sauna, guided runs on amazing trails including runs on segments of the UTMB/CCC course, group sports nutrition workshops, one-on-one nutrition coaching sessions (including optional blood work analysis and sweat testing) plant-based meals prepared by our private chef, personal sports physical therapy, a gift bag, and being part of a fun, like-minded group with who you can share adventures on & off the trails!
If you’re interested in nutrition coaching with Vic or his retreat in France, visit mtnsportsnutrition.com or message him on instagram @mountain.sports.nutritionist