I’m not going to argue that peanut M&M’s are delicious and a bit nutritious, but are they really the perfect mountain food? Does leftover pizza make the best alpine-start breakfast? Can you climb all day on only Clif Bar products? I’ve tested several of these theories myself, and I’ve spent a lot of time talking nutrition with endurance athletes. Everyone has their own preferences, but there is some science behind what you should be eating and when you should eat it during a long day in the mountains.
1. Throw your low-carb diet out the window: You need to have adequate glycogen stores built up in order to fuel your first 30 to 90 minutes of exercise. After the first hour or so, your glycogen stores will be depleted and your body will need to metabolize fat for fuel. Yay! We love burning fat, right? Well, most of us have anywhere from 40,000-100,000 calories stored in our existing body fat, just waiting to be tapped into for fuel. However, you need carbs available in your bloodstream to break down those fat cells into fuel. Simple carbs digest the fastest and provide the quickest fuel supply to your bloodstream. Complex carbs and protein digest slower which gives you a longer-lasting supply of fuel, instead of the quick spike and subsequent crash that comes from simple carbs. I try to alternate between the two at each snack break: protein bar at break #1, Clif Shot Blox at break #2, peanut butter crackers at break #3, more shot blocks at break #4, and so on.
2. Timing is everything: Since you burn through carbs so quickly, it’s important to refuel every hour or so. I can usually go the first 90 minutes before I get that “need-food-right-now” feeling. From there on, plan to stop every 60 minutes for refueling. Limit your breaks to 10 minutes or less, just long enough to eat 150-250 calories and hydrate (you might require more calories depending on your weight, intensity of your hike, and how well your stomach tolerates it). Mentally, I can break down a 6-hour climb into 1-hour chunks of effort between snacks, which makes it easier to keep moving until the next break and not feel overwhelmed by the effort. This also applies on the way down! Hiking downhill feels so much easier, but in reality your muscles are working hard to slow you down on every step. Bonking on the way down feels just as terrible as bonking on the way up, so I suggest throwing protein-based snacks in your pocket to munch on as you trudge down.
3. Eat for recovery: You need protein to repair damage to your muscles from the exertion of hiking, carrying a heavy pack, climbing, etc., but since it’s harder to digest than simple carbohydrates, you want to take in most of your protein while you’re at rest (or start your protein in-take on the hike out as I suggested above). On multi-day hikes or climbs, dinner should be heavy in protein and carbs to replenish what you’ve lost throughout the day and help your muscles repair. Breakfast is always the tricky part: if you have an early start and not enough time to digest a high-protein breakfast before you’re moving (2-3 hours), maybe try drinking a protein shake? Protein powder doesn’t weight much and might be more palatable than those Mountain House freeze-dried eggs. However, if you’re starting at 1am and you’re still full from dinner the night before, simple carbs like an energy gel or Shot Blox should be all you need until your first snack break.
4. Fiber is not your friend: In short, fiber makes you poop. Pooping is great for colon health, and I’m all for it before starting a hike! But, eating too much fiber while exercising can cause distress. When you eat, blood supply gets diverted to your GI tract to aid with digestion and absorption of nutrients. While climbing or hiking, your muscles need that blood supply, so your digestive tract gets neglected. Non-soluble fiber is also non-digestible, so it sits in your GI tract until enough water can be pulled in to flush it through. Think about corn…you eat it today and see it again tomorrow. I know, eww, but it’s a fact of life. Fiber also requires fermentation to digest. Fermentation equals gas, and while your hiking partner can escape by going ahead of you, the bloating that comes with it might leave you feeling like you shouldn’t have left the trailhead toilet. Crackers and rice have soluble fiber, which is usually more tolerable versus vegetables like spinach, cucumbers, or the aforementioned corn. Keep your fiber in-take to a minimum during a climb, and save the healthy salad for dinners at home.
Even when I eat according to science, I sometimes have moments (or hours) when I feel awful on big days. When that happens, I slow my pace or rest longer after eating to allow my body to process my food and I can usually come out of it feeling stronger. The important thing is to use every opportunity to find out what foods work best for you. If you find out that a sleeve of Oreos works best for you on a climb, rest assured no one will judge you while you power on by them like a rockstar!
– Nikki Brown, CSCS
Author & Contributor
Nikki Brown is a Certified Strength and Conditioning Specialist with a passion for skiing. When she’s not in the gym, she’s playing in the mountains. Nikki and her husband ski every month of the year, and are currently working on climbing and skiing all of the PNW volcanoes.