I gave [the cook] leave to kill our little dog, (Tlamath,) which he prepared in Indian fashion; scorching off the hair, and washing the skin with soap and snow.… Shortly afterwards … we had to-night an extraordinary dinner—pea-soup, mule, and dog.
That was John C. Fremont as he celebrated nearing the end of the first winter crossing of the Sierra Nevada in 1844. You can’t really get to like the guy. Not only did he eat the pet dog that had accompanied him through months of adversity, but he and especially his guide, Kit Carson, were notably fond of slaughtering Native Americans, using sabers on the women and children to save gunpowder. Not much of a gastronome, either. Times change, thankfully, as have ideas about nutrition for mountaineers.
New research on the performance of athletes at altitude shows conclusively that what a mountaineer eats and drinks profoundly affects health, body weight and composition, ability to recruit energy stores, recovery time after climbing, performance on the mountain, and even cognitive acuity. Gone are the days when a mountaineer simply tossed a salami and a block of cheese into his pack, threw a rope over his shoulder, and suffered to the summit. New-school mountaineers take advantage of the progressing understanding of optimal endurance nutrition and new science on performance at altitude. Top-level mountaineers are among the most fit athletes in the world, but even weekend climbers on roadside attractions should think of themselves as endurance athletes—that will bring nutritional requirements into focus. You don’t have to be a super alpinist to take advantage of the best science; even weekend peak baggers can perform better, enjoy themselves more, and climb more safely when their bodies are optimally nourished.
The body deals with nutrition differently during exercise and when recovering, so I’ll separate my discussion into nutrition on the go and nutrition for recovery. I’ll mix science and practical recommendations.
Energy consumption is measured in calories; for consistency with food labels I’ll use dietary calories; they’re each equal to 1,000 science lab calories (kcal), which are themselves equal to 4.2 joules, to be insufferably scientific. Calorie consumption measures how much energy your body is putting out to move, stay warm, digest food, and think about things. Maximum calorie consumption for a given weight is indicative of an individual’s fitness. The calories burned by a couch potato are called basal metabolism; this daily figure is added to calories burned by activity. You can approximate your basal metabolism (assuming you are the reasonably fit climber I refer to throughout this chapter) by multiplying your weight in kilograms (pounds divided by 2.2) by 13.7, adding 66, adding 5 times your height in cm (inches times 2.54) and subtracting 6.8 times your age. Females use 9.6 × (wt. in kg) + 65.6 + 1.7 × (height in cm)−4.7 × (age in years). Simple enough? Above basal, most calories are burned in muscle. Even couch potatoes burn about 50 percent more than basal, just changing channels.
Mountaineering activities result in calorie consumption of from 300 to 800 calories per hour. Trained athletes can go as high as 1,000 cal/hr; world-class endurance athletes can kick out 1,500 cal/hr or more for limited periods. You can get at this number knowing that it requires about 5 calories to burn a liter of oxygen; if your VO2max (detailed in the next chapter) is 50 ml/min/kg and you weigh 165 pounds (73.6 kg), that means your absolute maximum burn rate will be around 1,100 calories per hour (but you probably couldn’t go that hard for a whole hour). Calorie consumption for an entire day can range to 6,000 or more at altitude and in the cold. Cyclists in the Race Across America may burn 10,000 calories for days on end, but the RAAM is basically a battle of metabolic capacity; mountaineering presents challenges that preclude anywhere near this level of exertion. My climbing buddies refer to 4,500 calories as an “El Cap day.” That’s a good number to figure for a hard, but not debilitating, day; a fit mountaineer could string together many of these days, given proper rest and nutrition. Many reasonably fit mountaineers will find a 4,000-calorie day challenging, and in a moderately sized group, attempting 4,500 will probably exhaust at least one member. Your vigorous hike up the trail to base camp may require only a 3,000-calorie day.
During athletic activity your body will consume water, calories, and micronutrients (minerals, electrolytes). During high-output exercise it isn’t possible or desirable to replace 100 percent of the water, calories, or electrolytes you expend. About 35 to 45 percent (call it a third to a half) repletion of water, calories, and electrolytes is optimum to avoid gastrointestinal violence and performance degradation (the gut bomb). Another way to say this is that humans can resupply energy from ingested food only up to a maximum of about 280 calories per hour (depending on lean body mass), irrespective of output. This means that the remainder burned during the day must be replaced at sit-down meals. Let’s see how this partial repletion principle plays out, starting with water.
With all those calories being burned, your body’s core temperature will rise—exercise literally warms you up. A temperature of about 102 °F (39 °C) is to be expected, but your body must cool itself to prevent its core temperature from rising much higher. It does this mostly (at least 75 percent) by evaporative cooling of sweat. The efficiency of sweating varies with environmental factors (in high humidity you’ll sweat, but the sweat won’t evaporate and therefore won’t cool you as much), and it may be supplemented by convective cooling (a cool breeze), but you can figure on sweating about a liter (34 oz) of water during each hour of exercise. Heat, humidity, and exertion can raise that by a factor of three, and it will also be higher in cold dry air and at altitude. Some of this water comes from glucose metabolism (as much as a pint per hour), but most comes from your store of bodily fluids, which become increasingly concentrated as you sweat unless you deliberately replenish your water loss.
Unreplaced water loss (dehydration) is a bad thing. Take a look at the table to see what happens.
The importance of replacing water loss is reflected in the many admonitions to do so, from “drink before you are thirsty” to “hydrate or die.” Drinking at rest stops falls short of optimum; it’s much better to drink frequently from a handy bottle or a bladder inside your pack. To attempt to rehydrate at the end of the day is not only old-school; frankly it’s stoopid in light of modern science—and it’s ineffective because of the limit your maximum gastric emptying rate places on water absorption, to say nothing about the performance degradation you will inflict on yourself as you become increasingly dehydrated during the day.
How much can you drink? Your stomach can absorb up to a liter per hour if you keep it full (600 ml is about full) and if the weather is really hot and humid; otherwise figure on maximum gastric emptying of about 750 ml (25 oz) per hour with a filled stomach. It’s actually possible to drink too much water; it will sit in your stomach and impair performance, and in extreme cases of exertion and sweating, it could lead to hyponatremia (debilitating sodium depletion) unless you also thoughtfully consume electrolytes. Twenty ounces per hour is a good number to use as a repletion target for just about any athlete on the go; in extreme circumstances, that would go only slightly higher, and you’d want to superhydrate with a glycerol supplement—beyond our scope. Don’t kid yourself and think you can get away with less—your performance will suffer, and your body will, too. Even if you’re drinking the right amount of water, it may not be doing you enough good because it’s poorly absorbed in your stomach. For proper, maximal absorption (gastric emptying), your fluid intake needs to be isotonic.
Here’s a summary of recommendations for adequate hydration:
Drink 16 to 24 ounces (475 to 710 milliliters) of water, in several aliquots, during each hour of strenuous exercise. This is likely less than you are losing through sweating and breathing, but it’s the most your stomach can absorb; be sure to make up the difference later.
Drink an isotonic carbohydrate solution containing electrolytes.
Drink another 80 to 100 ounces (2 to 3 liters) of water each day when you are vigorously active, in addition to your sweat replacement scheme.
In cold weather, sweating will decrease, but dry air and high altitude cause more respiratory water loss for the same activity—up to twice as much as at sea level.
Water is more readily absorbed when it’s cold; freeze a bottle (or even smarter: half a bottle) or stuff yours with wet snow to keep your hydration source cool.
Use caffeine advisedly; in high doses it helps endurance athletes on the go, but it’s a diuretic when consumed at rest. Some energy gels provide 20 to 40 milligrams (equivalent to about a fifth to a half of a cup of coffee) per serving. Read the labels carefully.
When you calculate anticipated water requirements, work out what you’ll carry, what you can obtain from streams or drips, and what you must obtain by carrying a stove and melting snow. If you have only the option of melting snow, it’s not efficient to carry more than about three liters, or quarts, of water.
In sweat you lose sodium, potassium, a little calcium, and smaller amounts of lots of other things. The sodium loss can be 1 or 2 grams for each hour of copious sweating. Potassium loss amounts to a few hundred milligrams per hour; other constituents are much less. Actual numbers are all over the map, because individuals have huge variations and heat acclimation reduces electrolyte loss. You’d suffer greatly if you tried to replace all the electrolytes you sweat out during the time you’re active; you’d probably vomit or cramp up. A better strategy is to replace about 200 milligrams of sodium per hour of exercise along with about 100 milligrams of potassium. Be sure your hydration fluid provides that, or do it yourself. Morton Lite, available in grocery stores, is about 21 percent sodium and 24 percent potassium, the rest is chlorine. If you mix two parts, by volume, of ordinary table salt (39 percent sodium) with three parts Morton Lite, you’ll have a mix that’s 29 percent sodium and 14 percent potassium. A heaping quarter teaspoon of this mix weighs about 2 grams and an eighth of a teaspoon provides an hour’s worth of the sodium and potassium you’re looking for; precision is not required. Your body has stores to hold you for at least three or four hours, and just about anything you eat, including most sports drinks, contain sodium and potassium, so replacing electrolytes isn’t normally an issue unless you’re drinking a lot of pure water and sweating like a beaver. If you’re obsessive/compulsive you could ensure, by your choice of maltodextrin gel or by another supplement, that you’re not only getting the right amount of sodium and potassium but also calcium, magnesium, and manganese chelates. Be sure you’re not overlooking the requirement to replenish electrolytes and that you restore daily net losses in the course of your sit-down recovery meals.
Remaining in your on-the-go nutrition planning is replacing the calories you burn. Here again, it’s not possible to achieve complete repletion. You may be burning 600 to 800 calories per hour (more at altitude and in the cold), but the maximum your body can ingest and process while you’re exercising is only 200 to 350 calories per hour, no matter how high your energy output. Any more will just hamper performance until it gets converted to fat. To get a slightly more accurate number for maximum repletion calories per hour, multiply your weight in pounds by 1.75 or figure 1 gram of carbohydrate per hour for each kilogram of body weight; a gram of carbohydrate yields four calories. Your most accurate personal number depends on your lean body mass, tolerance for food during exercise, and other individual factors. The best way to obtain those calories is from carbohydrates in liquid (solution) form. The solution should be isotonic for best absorption, but does this take care of the problem? Not quite.
Isotonic sports drinks contain 6 to 8 percent carbohydrates in the form of simple sugars. Simple describes pretty much all of them, and simple carbohydrates are pretty much all the same, too: “sugar” (table sugar: sucrose) is glucose + fructose, high fructose corn syrup is about equal amounts of glucose and fructose, and fructose and glucose are, well, glucose and fructose. A 6 percent sugar solution provides only about 120 calories in 20 ounces (carefully read the labels on those sports drinks). We’re shooting for closer to 300 calories in 20 ounces for optimum repletion. If more sugar were dissolved in the water to deliver the needed calories, the solution will be hypertonic (not to mention obnoxiously sweet) and will mostly sit in your gut until you secrete enough water to dilute it—just the opposite of your hydration objectives.
The answer is hydration fluid made with 18 to 24 percent maltodextrin. Maltodextrin is a carbohydrate, just like sugar, and it provides the same amount of energy—4 calories per gram or 113 calories per dry ounce—but it’s molecules are mostly much bigger. Maltodextrin is basically partially digested corn starch; it contains about 2 percent glucose, maybe 6 percent maltose (glucose + glucose), and about 85 to 90 percent polysaccharides (complex, but not too complex, carbohydrates). Data suggest that glucose polymers such as maltodextrin are absorbed and used more quickly than plain old glucose, especially after an hour or so of exercise. You may see maltodextrin rated with a dextrose equivalent (DE) number (dextrose is another name for glucose); lower numbers mean faster absorption in the stomach. A DE lower than 20 is good. That 18 to 24 percent solution of maltodextrin will be isotonic and will quickly provide about 300 calories in 20 ounces of solution, with only small amounts of simple sugars and no fructose. And it’s way cheap. Miraculous!
Another approach to drinking isotonic carbohydrate solution is to consume maltodextrin in the form of a concentrated gel (gel is the marketing term, but syrup would be more accurate), immediately followed by a drink of plain water. GU was the first such gel readily available in the United States, and it became famous among mountaineers; now there are many others, or you can make your own from bulk maltodextrin. Fortunately some of the others are formulated without fructose, most add electrolytes, but many make specious claims of benefits from trace ingredients. New-school mountaineers (and adventure racers) prefer to purchase maltodextrin gel in larger, 23-ounce (650 ml) bottles and transfer it to fist-sized, graduated 5-ounce flasks for on-the-go consumption. A 1-ounce gulp of gel (about 110 calories) washed down by two or three big mouthfuls of water (about 7 ounces or a third of your 20-ounce bottle) every 20 minutes is just the ticket to provide optimum repletion of both water and energy. The necessary electrolytes are formulated there, too. Set your watch to beep a reminder until you get into the 20-minute habit. If you find swallowing gel troublesome, you can dump the necessary amount into your water container to make your own energy drink (some flavors work better than others), or find new products that let you mix up maltodextrin-based sports drinks yourself. If you’re not working at high output, cut back on the gel and water, but don’t extend the 20-minute intervals.
Consuming maltodextrin this way has other benefits, the first being lower cost compared to the single-serving packets. There’s no temptation to discard those empty packets or their opening tabs along the trail, and no need to fiddle around with the gooey empties or store them in your pack. Your water containers will hold only plain water, so they’ll neither encourage the development of alien life nor preclude use of the water for other purposes. And there’s no complexity if you add more water or snow to your water container. Finally, maltodextrin doesn’t keep my teeth full of sugar or create the scum and aftertaste in my throat the way sports drinks do, but maybe that’s just me. There are a couple of practical cautions: some of those little flasks leak, so test them out first in zip-seal baggies, and the gel gets very thick in cold weather, so keep your working flasks close to your body for warmth.
Good old raisins and peanuts is definitely old-school. Trail mix is mainly low-grade fat and low-grade protein, and it’s difficult to digest, however yummy you may think it tastes—check the nutritional contents on the label. Don’t eat GORP or its variants for on-the-go nutrition. In general, for optimum performance, don’t eat fat and don’t eat solid foods of any kind, including energy bars, during high-output exercise. Those bars claim to be balanced for daily nutrition, not for consumption during vigorous exercise, and even that claim is questionable. Always aim for mountaineering food that’s high in carbohydrate and low in fat.
Don’t put your calculator away just yet. Let’s look a little closer at mountaineering nutrition, starting with a digression that will lead to sit-down nutrition planning.
Carbohydrate metabolism can be viewed simplistically as the conversion of glucose to work in your muscles. Muscles can’t simply pull the required glucose out of your blood stream because the limited amount there would be depleted in a few minutes of hard work. Since your brain runs on glucose and doesn’t store any, depleting glucose from your blood would be, well, brainless. Running out of glucose (the “bonk”) does indeed lead to cognitive dysfunction, though in males the principal cause of that may be testosterone oversufficiency. Instead of relying solely on blood storage, your body stores glucose in the liver and muscles in the form of glycogen, a polymer than can readily be converted back to glucose. Male athletes store about 90 grams of glycogen in their liver and 400 grams in muscle (about 2,000 calories total); female athletes store about three-fourths of that. Attempting to increase these stores is called carboloading—a shift to a higher fraction of dietary carbohydrate calories in the day or so before an event lasting more than an hour. Even this energy store will be exhausted after a few hours of hard exercise, so replenishing as much as possible—as much as the body can accommodate—during exercise is crucial for maintaining high output effort for an extended time. Replenishing the remainder of your glycogen debt with sit-down recovery meals is crucial if you expect to continue high-output effort on successive days.
The relative contributions of fat and carbohydrate to energy vary with exercise intensity. At low exercise effort your carbohydrate needs can be obtained from blood glucose and the conversion of glycogen. As your body continues hard exercise and faces depleting glycogen stores, the balance shifts to other energy sources: fat and protein. At effort near 40 percent of VO2max the availability of fat for energy reaches a peak, but the actual utilization of fat peaks at about 60 percent of VO2max. A single pound of body fat provides about 3,500 calories, so don’t worry about running out. The balance of fat versus carbohydrate used for energy shifts when an athlete is exposed to altitude and then re-adapts during acclimation. Burning fat is less efficient than the conversion of carbohydrates to energy, and fat can’t be converted directly to glucose or glycogen. Nevertheless, body fat becomes the fuel of choice during moderately hard exercise lasting more than a few hours. Then it should provide around two-thirds of your caloric requirements. Ingested fat inhibits gastric emptying and lowers blood glucose levels, so avoid consuming it during exercise. Conversion of fat to energy requires glucose, so when glycogen and blood glucose are thoroughly depleted, fat conversion nearly stops, and your body consumes muscle for energy—that’s bad. Promoting the conversion of fat to energy is the challenge. There are plenty of supplements that claim to promote fat utilization, caffeine among them, but the biggest factor in building your body’s propensity to make fats available for conversion to energy is protracted, regular endurance training—unwelcome news for couch potatoes, who were hoping for a pill.
Fat deserves a place in your recovery meal, but not because you’re ever likely to run out of this important energy supply during a typical extended outing. Fats containing omega-3 fatty acids help replete the intramuscular triglycerides that are a significant energy source during extended exercise, and fats in your diet support fat-soluble vitamins and supply essential fatty acids for things like hormone (testosterone) synthesis. Fat in your dinner also seems to keep you warmer at night. Don’t over do it by eating lots of fatty foods on longer, higher climbs; that old-school approach is nutritionally unsound. Getting an unnecessarily high fraction (more than 30 percent) of your sit-down energy from fat instead of carbohydrate tends to exacerbate the symptoms of altitude illness. On the other hand, mountaineering shouldn’t be thought of as a weight-loss or fat-reduction program, even though that often happens. There is anecdotal evidence that your body, when nutritionally stressed, attempts to spare its fat stores but that this mechanism can be fooled by eating a dollop of fat. I think I’ve seen this myself, based on the olive oil that’s in my “ten essentials for cooking,” but it’s for sure that your body won’t efficiently convert fat to energy if glycogen has been depleted and you’re in a state of bonk. I’ll spare you more complex details on fats, triglycerides, and essential fatty acids except to offer my personal admonitions to favor liquid vegetable and fish fats (oils) and to avoid solid animal fats, processed and hydrogenated fats, and tropical oils.
Protein, too, is thrown into the cooker to produce glucose during endurance efforts. About 10 to 15 percent (call it 
) of expended energy comes from the conversion of protein to glucose, a very inefficient process called gluconeogenesis. When I say protein, I mean your muscles. The amount you burn going full tilt is about an ounce (28 g) per hour—a few pills won’t replace it. Ideally, you’d replace protein in liquid form during any vigorous exercise lasting more than a few hours, but this proves to be problematic in practice, and protein can be difficult to digest when on the go. Once again, the best you could do is partial repletion. Because it’s difficult to maintain protein balance during exercise, it’s absolutely essential to replace it conscientiously in your sit-down recovery meals.
Protein is a class of complex molecules composed of amino acids; the ones that humans can’t synthesize are called essential amino acids. The amino acids most important to building or rebuilding muscle are leucine, valine, and isoleucine, in the ratio of 1:1:2. These are called the branched chain amino acids (BCAAs). Ideally you’d just add these to your hydration plan in order to avoid burning muscle for energy (catabolism—a bad thing). Throw in some alanine, too. There are numerous studies that show that supplementing these amino acids during recovery spares muscle mass, prolongs the ability for high-output exercise, and even improves mental function, even though it doesn’t boost raw performance. And they don’t taste too bad. The problem is that the amount of BCAAs you’d have to consume on the go (about 25 percent of 10 percent of the El Cap day calorie expenditure, or 5 to 10 grams per hour during exercise) is economically infeasible. You’re going to have to consume protein and break it down into amino acids yourself in order to get the BCAAs you need. There are several options.
You might think that a whole protein such as meat or eggs would be your first choice. You’d be wrong. There are several ways to rank protein sources according to how efficiently they provide the amino acids humans need and whether certain components are available undenatured, not just whether the protein has a desirable amino acid composition; one such index is the Protein Digestibility Corrected Amino Acid Score. At the top of the quality list is whey protein. Cow milk is about 6.5 percent protein; of that, 20 percent is whey protein, and the balance is casein (or “curds” as Miss Muffet sat down to eat). Roughly 25 percent of whey protein is BCAAs in approximately the correct ratios. There are several ways of refining whey protein, a byproduct of cheese manufacturing, and the results find their ways into supplement powders and protein bars along with other often unidentified bulk protein sources. Cross-flow microfiltration whey isolate is apparently the best form, made by a process patented by Glanbia Nutritionals. It is available with 99 percent undenatured protein. Whey “concentrates” are less concentrated and cost half as much.
Next on the list is soy protein in its various qualities. Then conventional whole protein from egg whites followed by meat protein (light skinless chicken and fish). Casein is down the list, too. Soy doesn’t build muscle quite as well as whey and doesn’t have as favorable a balance among the BCAAs, but it causes less ammonia waste, so soy might be the choice for consumption during or immediately before exercise. It also contains phytochemicals that are proving to have numerous health benefits. In principle, partially digested (hydrolyzed) protein would be the best form to consume for easy assimilation during exercise; in practice, the taste of hydrolyzed protein is a gastronomic disaster. Last on the quality list is whatever protein you eat in the course of casual consumption—catch-of-the-day protein.
Various formulas have been offered for daily protein requirements, but it’s clear that athletes need more than couch potatoes. Plan on 1.2 to 1.7 grams daily per kilogram of body weight (about 0.5 to 0.8 grams per pound), depending on exercise intensity and the quality of the protein; teenage athletes need more. This, as always, refers to dry weight. It’s a surprisingly large amount of protein by the time it’s eaten (a McDonald’s Quarter Pounder contains less than 30 grams of dry protein). Drink the suggested amount of water to ensure removal of uric acid waste from protein metabolism.
Among the protein and amino acid supplements you may come across, you’ll see glutamine. It’s the most plentiful amino acid in the body and in wheat protein; claims have been made that supplementing 5 grams before and after workouts, along with BCAAs, helps increase muscle growth. The actual science is inconclusive, and I’m unconvinced that quality whey protein wouldn’t do the same thing better.
I recognize that not all mountaineers will burn 4,500 calories every day of their outing, and that the optimal nutrition I’m describing here may be difficult for many to achieve. I’ve presented it as the best recommendation current science has to offer for protracted, high-performance, high-output exercise. Then there’s reality.
One aspect of reality is that everyone’s appetite suffers at altitude. Many climbers lose 1 to 2 pounds per week, often several times that in the first week of an expedition at altitude. Caloric needs increase by 10 percent or more above 10,000 feet, but appetite goes down by at least that amount. There are many reasons for this, principally “hyperbaric hypoxia,” but it’s common for mountaineers to consume 60 percent or less of the calories they expend—that’s a worry. Cramming enough food down your throat when you sit down to eat is difficult, but essential. This problem is not to be taken lightly; addressing it requires deliberate and concerted dietary management and forced eating, especially on extended outings at high altitude. You may hear statements along the lines of “any calories are good calories at altitude,” but the more you succumb to junk calories, the more your performance will suffer. Strive to maintain a high-carbohydrate diet, even though you must force down powders and gel in addition to tolerable real food. On short trips you can ignore dietary recommendations and just eat whatever tastes good enough so that you’ll eat enough, irrespective of any nutritional profile—live off the fat of your waist. On longer outings, and especially at altitude, you need to plan much more thoughtfully for total calories, caloric balance, and palatability.
Well, let’s hope not. Backpackers may have the luxury of preparing elaborate cooked breakfasts, but climbers usually need to get going as soon as possible, often before daylight. Our breakfasts tend to be, as Duncan Hines said, “the bolt it and beat idea of dining.” A big breakfast, concocted without regard to glycemic index, needs to be given several hours to make it out of the stomach before exercise commences. If that amount of time isn’t in the cards, perhaps because you wisely conclude that sleep is more important, take more care to eat breakfast thoughtfully. If you’re on a short casual climb, cold pizza makes just as tasty a breakfast in the mountains as it does at home; it beats Oak Meal or Cream of Weeds. I avoid cooking breakfast to save time and fuel; I’ve learned to tolerate body builder powder in cold water—sort of a high-tech powdered instant breakfast mix without fructose. If you haven’t put away that calculator and want to follow the best science, start your day with a light carbohydrate and protein breakfast about a half hour before you hit the trail; that snack would contain about 50 grams of carbohydrate and 5 to 10 grams of soy protein. If you start your day with a big slug (two ounces) of energy gel, wait until you’ve started warming up. Whatever you eat for breakfast, don’t eat too much; that would bog you down, and you’ll be throwing more fuel on the fire as soon as you get moving. If you expect a hard, hot day, ensure that you are fully hydrated by slugging down a 20-ounce bottle of isotonic water about two hours before the intensity begins.
Once you’re moving and warmed up, begin your on-the-go nutrition and hydration plan; go easy on the gel in the first hour. After the first hour, maintain the 250 to 300 calories from maltodextrin gel and 16 to 24 ounces of water, spread out over each hour. If you’re clever, you could add 20 to 40 calories from soy protein per hour (about a half ounce of protein stirred into a 5-ounce flask of gel), but the science is not entirely conclusive on the real value of doing so. I find that the gel regimen keeps me going, but doesn’t keep my ribs from banging together once breakfast fades from memory. That’s the purpose of lunch. Lunch should not be a big calorie hit; just something quick and easy to get down that hopefully emphasizes protein—another bolt-it-and-beat-it snack. My current favorite is tuna repacked into a 150 ml specimen jar (ask your doctor), dumped into a French roll and slathered with mayo from those little food service packets. One of my partners likes cream cheese and jelly on a bagel. Pick your personal favorite snack, but make it easy to digest and, unlike my examples, deemphasize fat. Some folks like Intermountain’s Bear Valley Meal Packs—basically oversized energy bars that pack over 400 calories into not quite 4 ounces; they have about the same amount of protein as that can of tuna, but its quality is unknown and probably not as good. Cooking is definitely out unless you also need to melt snow for water. Don’t be surprised that you become chilled as your blood shifts from muscle to gut, or that you feel like it’s nap time right after lunch; minimize these effects by eating light and fast. After your lunch snack, it’s back to the carbo and water routine.
When things wind down, whether it’s back in base camp or setting up a new camp, you may be tempted to ignore your empty stomach and begin some important project. That would be a mistake. Immediately after vigorous activity stops is by far the best time to refuel for recovery; the longer you wait, the less efficiently you’ll replace expended glycogen and conserve muscle protein. The best plan would be to consume a concoction of 200 grams of complex, high-glycemic-index carbohydrates, or about 1.25 grams per pound of body weight (an amount equivalent to about eight servings of energy gel), along with 50 grams of whey protein, washed down by plenty of cold water. In other words, a carb to protein ratio of four to one. These amounts are higher than were once thought effective, but ingestion immediately after exercise is well accepted. The idea is that the protein both promotes repair of metabolized muscle and causes a heightened insulin release that enhances glycogen repletion; this protocol also reduces illness, reduces muscle and joint problems, and reduces susceptibility to heat illness. Details are being actively researched. Mix gel plus whey protein powder in advance, so that you can scarf it down as soon as possible; it will have the consistency of runny peanut butter—the sweetest-tasting peanut butter ever to cross your tongue. If getting that down is challenging no matter how hungry you are, it’s nearly as effective to consume half the amounts immediately after you stop and finish off the remainder over an hour or so as you are setting up camp, building an igloo, or preparing that seven-course sit-down meal. Promptly getting glucose into your blood is what’s most important to glycogen repletion, so eating a complete meal soon after you stop exercising, especially one containing fat and fiber, is much less beneficial than eating only carbohydrate and protein solution. If you opt for something other than maltodextrin gel to supply carbo calories, look to high-glycemic-index carbs that go quickly into your blood stream, such as quick-cooking rice or instant potatoes; avoid fat until later and always avoid fructose altogether. Be wary of one down side: you may get an insulin spike and crash that can lead to a party of fatigued mountaineers who are very, very crabby.
If you’ve successfully replaced 35 to 45 percent of your fluids, energy, and electrolytes consumed during exercise, your first concern at the end of the day will be to drink enough water to rehydrate and support optimal renal function. This isn’t the same thing as allowing yourself to become dehydrated during the day and then attempting to rehydrate afterward—that won’t work. Don’t depend on your sense of thirst; it may be depressed by exertion at altitude. Aim for 0.5 to 0.6 ounces of water for each pound of body weight (35 ml/kg), in addition to your on-the-go intake. You’ll have to consume about 150 percent of what you intend to replace, due to losses from normal urination, high-altitude-induced diuresis (maybe an extra half to a full liter per day), and increased respiration losses (up to 1.5 liters or quarts of water per day; twice what you’d see at sea level, and at very high altitude, twice that again). Some water is also lost in feces, and some is gained as a byproduct of glucose metabolism. Alcoholic beverages don’t count, and coffee counts only half, because they are diuretics. Plan on 2 to 4 liters or quarts per day, made isotonic with dissolved carbohydrates unless consumed during meals, in addition to your on-the-go hydration intake. Failure to achieve adequate hydration will depress your appetite even more than it will already be depressed by high altitude, and can augment symptoms of altitude illness. The only down side is that you’ll pee like a racehorse, but that’s a good thing if you’re careful to replace minerals and soluble vitamins that are washed out. In Chapter 20, Training for Mountaineering, you read that a principal gain of cardiovascular training is an increase in circulatory capacity; when you lose water, the bulk of the loss comes from blood plasma, so maintaining hydration is absolutely essential to maintaining cardiovascular fitness on an extended outing.
Next, consider total energy replacement. We’ve been looking at 4,500 calories as the burn on a solid day of mountaineering, but it can easily be more. Some of that you’ve already replaced during your on-the-go nutrition/hydration scheme. The optimum ratio of macronutrient calories is about 65 to 70 percent (two-thirds) from carbohydrates (at 4 calories per gram), 20 to 30 percent (one-fourth) from fat calories (at 9 calories per gram), and 10 to 15 percent (one-eighth) from protein (at 4 calories per gram). These ratios work out to around 2.1 pounds (960 grams) of total dry weight per day to hit 4,500 calories. Even “dried” food contains 5 to 10 percent water, so you end up looking at 2.25 pounds or about one kilogram per day of total “dry” weight, on-the-go plus sit-down recovery food. Interestingly, this is the same weight worked out through trial and error by thoughtful mountaineers, long-distance backpackers, and others who go hard for days on end. If you ignore the science and eat an old-school diet, you’ll have to accept suboptimal performance as your reward.
Typical appetite loss at altitude, especially in the first few days, means that getting this amount of nourishment into your gut will be a challenge. Of more scientific concern is that 650 grams (23 ounces), or about 2,600 calories, is about all the carbohydrate that a human can convert to glycogen stores daily. Any carbohydrates eaten in excess of that get converted to fat; fructose in particular is more likely to be converted to fat rather than glycogen. The precise amount you can convert depends on your lean body mass and level of exercise, so if you’re a really big guy and go very hard all day, that figure could go up by 50 percent, but you get the picture. This limit, in combination with an optimum balance of fats, protein, and carbohydrates, places a total limit on daily useful caloric consumption of around 4,400 calories, irrespective of the amount you actually burn. This figure matches nicely with our model El Cap day, but the 2,600 calorie maximum places a limit on attempts to carbo-load—you can end up just fat loading, and for most of us, carbo unloading is a greater concern.
Those 6,000-calorie burns hauling heavy loads on long Denali days will cost you. Hopefully the cost will be in body fat that you can do without, but don’t compromise on protein, or you’ll lose muscle, too. On a day like that aim for 0.8 grams of protein per pound of body weight. That’s around 140 grams (5 oz) dry weight; consuming that amount from native sources can be daunting.
On typical outings of a day or so, the guide for a mountaineer’s dinner is comparable to that for breakfast: forget nutritional science and eat what tastes good and is easy for you to digest. For dinner, eat foods that are easy to prepare, and eat all your appetite will tolerate. I’ve been discussing powder as if it were food, and indeed powders and gels make good and easily computed adjuncts to real food, but their sparse profile of micronutrients, absence of components like soluble fiber, and marginal palatability make them unsuitable for steady main courses or as substitutes for that rarity of modern life, a healthy diet. Unless you’re an astronaut or nutritional scientist, eat well-balanced real food when you can, even though you consume powder when it’s more convenient during critical stages of a climb.
On short outings you’ll be eating to accommodate your attitude more than attempting to maintain a perfect energy balance. Stop by a bunand-run on the way to the trailhead, if that’s your pleasure. On excursions of only a day or two, it may be more efficient to carry ready-to-eat sandwiches and forgo cooked meals and the means of cooking them. If cooking is going to happen, I like to bring semi-prepared food, like fresh tortellini, a prepared sauce in a zip-seal bag, and freshly grated Asiago cheese. On the outing this is easier to prepare than freeze dry, and it actually cooks faster and so uses less fuel (I often get by with a homemade hexamine stove, and you can pour boiling water right into a reusable O.P. Sak zip seal baggie just like into a freeze dry packet); I’m willing to carry an extra ounce or two to get the flavor that my appetite needs for encouragement. On longer outings I bring home-dried delicacies. Most backcountry cooks follow a similar principle: if you carry spicy condiments, you can make a tasty meal even out of grass and pinecones (well, I think I’ve seen it done). I like fresh garlic for its flavor (and its claimed benefits for altitude performance) and fresh Italian parsley for its durability in the backpack and ability to impart a fresh taste to any entrée, even freeze dry. Speaking of freeze dry, survivalists may swear by it but it’s very old-school for mountaineers. Because freeze-dry packaging is so wasteful, it has no weight advantage over carefully selected dry food, and its cost is certainly out of proportion to its nutritional value. As an example, Bear Creek powdered soups average ¾ of the weight for the same number of calories from freeze dry. If you shop carefully, you can find plenty of tasty dried foods at your supermarket; start with flavored basics: instant potatoes, instant rice, and ramen noodles; then work your way into exotica. Look for foods that require minimal cooking time and no boiling. The boiling temperature of water drops by about 1 F° for every 540 feet of altitude increase (1 C° for every 275 meters), so boiling times increase (about double at 5,000 feet), but not cooking times at lower temperatures. The lesson is to avoid foods that require actual boiling. Anytime you select prepared foods, check the Nutrition Facts label to see just how many fat versus nonfat calories you’re getting; be prepared for disappointment.
If you’re truly interested in optimum nutrition for athletic accomplishment, you’ll have to forgo the cavalier advice I’ve given about eating whatever tastes good. What you eat has a tremendous effect on your physical and mental performance. An athlete cannot hope to approach her full performance potential unless she eats a carefully planned diet. Such a diet would be one that all agree is “healthy,” but few people actually follow. Start by dumping any fashion diet you may be on or considering and aim for the caloric balance among protein, carbohydrate, and fat that I’ve already given. You’ll have to get your protein from very lean meats (not beef) and isolates, get your sedentary carbohydrates from low-glycemic-index, complex sources, and minimize fats, especially processed and animal fats. Ditch fructose, even in honey but especially the omnipresent high-fructose corn syrup. Plan on eating lots of cruciferous vegetables (brassica), tomatoes, and highly pigmented vegetables—which will also help you get a healthy 35 grams of fiber each day. The benefits from such a diet begin to kick in after a couple of months. The challenge for mountaineers is that such foods have high water content and cook slowly, making them impractical for extended outings if prepared fresh—hence my recommendation to prepare your own meals and dry them in a food dehydrator. Americans who actually adhere to such foods are dietary deities.
I haven’t yet mentioned replacing electrolytes lost in sweat that were only partially replaced during your on-the-go scheme. If you eat a reasonably balanced sit-down meal, you’ll replace basic electrolytes without supplementation, along with calcium, magnesium, and most of the other minerals. It doesn’t hurt to supplement electrolytes, because any excess washes out quickly, but don’t overdo it in hopes of eliminating cramps or out of sweat-loss paranoia. One serving of just about anything contains around 300 mg of potassium; bananas are not nearly as good as preserved dried fruit. An easy source of known amounts of potassium is Morton Lite salt, which is about 21 percent sodium and 24 percent potassium (table salt is about 40 percent sodium; the remainder is chlorine); you might add extra Morton Lite to your mountaineering meals, but drink plenty of water. Eating a teaspoon of salt doesn’t work.
There is a wide range of substances subsumed under the moniker of vitamins or nutritional supplements. Since athletes require more food for energy and recovery, you might expect that they’d benefit from consuming more than the Dietary Reference Intakes (formerly the Recommended Daily Allowances) of vitamins. In fact, it appears that athletes benefit from having several times the RDAs (or DRIs) of vitamins in their diets, although there’s no commercial incentive to work out the exact amounts and benefits for individual micronutrients. There’s a wide spectrum of opinion on the general subject of supplementation. Medical professionals have been schooled to preach that if you eat eight to ten servings of fresh vegetables daily, you’ll get the recommended allowances, and that’s all you need. That view is definitely old-school and is falling out of favor except among drug-dispensing professionals and within the government, their advocate. The problem with recommending a healthy normal diet is that a normal diet isn’t healthy. Anti-vitamin folks and drug companies constantly produce unresearched scare stories about vitamin toxicity; these inevitably prove to have nothing to do with vitamins and the stories fail to compare the danger to, say, aspirin, which kills thousands of people every year. My favorite scare stories are about how you might die from taking vitamin A supplements. If those stories were ethically honest, they’d have to say that the only instances of vitamin A toxicity have been caused by eating the livers of animals who store high concentrations of retinal ester (sharks, dogs, and, principally, polar bears), so the ethically honest conclusion isn’t “so don’t take supplements”; it’s “so don’t eat too much polar bear liver.” The conservative American Medical Association is now recommending a one-a-day multivitamin in order to promote general health and even recommends omega-3 fatty acids in supplemental form. Nor do I care much for the concern about “expensive urine”; if you want truly expensive urine, drink beer. At the other extreme are supplement fanatics, who can lose sight of sound science. I’m closer to the latter view—a confessed recovering supplement guinea pig—but I wouldn’t recommend it as a place to start. Micronutrient supplementation is a lifelong daily commitment to long-term benefits, combined with skeptical evaluation of mostly bogus commercial claims.
One “supplement” that’s now in favor is aspirin; the conventional wisdom is to take one baby aspirin (81 mg) daily to prevent heart attacks and some forms of cancer and maybe to counter some consequences of chronic NSAID use. Some mountaineers increase that to a full 325 mg every 8–12 hours when over 10,000 feet, in order to relieve headache due to high-altitude illness; don’t take that much aspirin for many days unless you really need it.
The B-complex vitamins are required for production of energy and for rebuilding muscle after exercise. There is evidence that, for athletes, the requirements are several times more than the usually quoted recommended daily allowances (or dietary reference intakes). One B vitamin, riboflavin, or B2, turns your urine bright amber, almost fluorescent in high mountain sunlight. In my opinion that’s a good indication that you’re getting enough water-soluble B vitamins; consider a multivitamin supplement if your urine is merely “straw colored” or “clear.” On the other hand, downplay niacin (vitamin B3), if possible, prior to and during exercise, because it appears to reduce the metabolism of fat for energy.
Antioxidants protect cell membranes from oxidative damage; these include selenium, lipoic acid, vitamin C, and the fat-soluble vitamins E, D, and A, or beta-carotene, which the body converts to vitamin A. Since endurance athletes have 10 to 20 times higher oxygen consumption than typical sedentary television watchers, you might think that supplementation of antioxidants would be a good idea for us. The science isn’t conclusive; some research finds appreciable but not dramatic benefits, and other research finds none. The studies that find no benefits are invariably conducted using laughably small doses compared to what supplementation enthusiasts consume. Studies at high altitude have shown that vitamin E improves exercise performance, and that vitamins C and E improve recovery after strenuous exercise. The amounts consumed were many multiples of the DRIs or RDAs—comparable to typical supplementation quantities. As far as I know, all the studies on antioxidants and mountaineers at altitude have shown beneficial results in terms of maintaining appetite and VO2max, indicating that antioxidant supplementation is a good idea under these stressful conditions. Other than cost, there are no down sides.
Calcium supplementation is no longer controversial, especially for female athletes who eliminate dairy, restrict calories, or suffer menstrual dysfunction; the amount of calcium should be balanced with about half as much supplemental magnesium. Calcium supplementation has been shown to promote fat metabolism and help manage body composition, though the effects are modest. I suspect that vitamin D supplementation will soon be widely recommended, especially for dark-skinned people or those who bundle up all year. Supplementing trace minerals, such as selenium, germanium, manganese, chromium, vanadium, and boron, is becoming less controversial as they are depleted from tilled soil and therefore disappear from our food supply, but there’s little evidence that supplementing them has ergogenic benefits for athletes. It’s generally recognized that zinc consumption is below the 1989 RDAs for most of the American population. Zinc preserves immune function that’s likely to be depressed in athletes. Zinc’s also involved in growth, muscle building and repair, and energy production. Its best natural sources are animal protein and fats, which may be in short supply for mountaineers, and zinc is especially likely to be deficient in athletes who wisely adopt high-carbohydrate diets. Conservative supplementation of minerals is cheap and safe; if you’re not sure of getting at least 20 mg of zinc daily, give serious thought to supplementation. Iron supplementation, on the other hand, is not beneficial except for the tiny fraction of the population known to be anemic, most of whom are female. If that’s you, you need serious medical intervention starting with a blood test. In industrialized countries there are about twice as many men suffering iron oversufficiency compared to deficiency, and 2 percent of people of northern European descent have a condition known as hemochromatosis, in which damaging amounts of iron are retained in the body’s organs. Iron promotes free radical production, a bad thing, and a high intake of iron, especially in combination with manganese supplementation, may be related to increased risk for Parkinson’s disease—in addition to making you constipated. I recommend choosing multivitamin supplements that specifically exclude iron—an indication they’re thoughtfully formulated according to modern science.
Beyond these basics there are a bazillion sports supplements vying for the wallets of endurance athletes, all claiming astounding benefits despite the small amounts of unproven active ingredients they contain—it’s a multibillion dollar industry, after all. I consider myself well informed on these matters, and sympathetic, too, so I’ll make a recommendation to get you started: save your money. Focus on training and the basic nutritional guidelines I’ve just offered—that’s complex enough. Be happy that success in mountaineering depends on so many different factors that you can ignore any purported marginal gains from sports supplements. The other option would be to give it serious study in peer-reviewed journals; after a year or so you’ll have done a lot of reading, will have incurred a hefty bill for broadband services, and may have shelves full of expensive supplements, but you’ll end up making the same recommendation that I have. In arriving at the following comments on specific supplements, I looked at nearly 500 scientific articles, including review articles, in journals as recent as the winter of 2004; all the many other supplements that I don’t mention that you may find being hawked by supplement manufacturers either have inconclusive or contradictory evidence supporting their effectiveness in human athletes, or when properly tested have been shown to have no significant benefit, or are dangerous. There are very few published studies on the effects of combining more than one supplement.
Phosphate loading has been studied for decades; it’s been found to increase maximal oxygen uptake, raise anaerobic (lactate) threshold, increase power at anaerobic threshold, and improve endurance exercise capacity by 8 to 10 percent, without increasing heart rate or lactate production. That’s an amazing benefit, comparable to blood doping with the banned drug EPO (erythropoietin), yet sodium phosphate is cheap and nontoxic. Sodium phosphate could be especially interesting to mountaineers, because it’s been shown that EPO improves respiratory acclimation to hypoxia. Phosphate supplementation is effective for endurance efforts; it does not augment high-intensity intermittent exercise. The complete story of why phosphate loading is effective is still being worked out, but it seems to be more than its buffering effect on lactate. The loading that’s been studied most consists of consuming one gram of trisodium phosphate (about a quarter to a half teaspoon, depending on the grind) four times a day for five days prior to your most important day; dissolve it in sports drink or orange juice because it’s too caustic for many to keep down in pill form. Mix up an entire day’s supply in advance, or even the complete loading amount. The benefits seem to last for about ten days.
There are several forms of sodium phosphate; the one shown to have considerable benefit for endurance athletes is the tribasic hydrate: trisodium phosphate dodecahydrate, Na3PO4 • 12H2O. That’s right: plain old TSP, the caustic agent that was taken off the market as an industrial cleaner when it launched concerns about nonbiodegradable products. The main impurity is sodium hydroxide: drain cleaner. Of course, the studies on athletes have been done with food-grade TSP; it is Generally Recognized As Safe by the FDA and has been safely used for many years, particularly in processed cheese. Apparently potassium and calcium phosphate aren’t effective, and it seems the dibasic sodium form used in the now discontinued PHosFuel probably isn’t either, for reasons beyond my ken. Chronic excess phosphorous intake may cause calcium loss from bones, so phosphate loading should be restricted to only several times per year, and the loading period should not be increased lest your body overadapt and begin peeing out more phosphate than it’s taking in. Phosphate is cheap, safe, effective, and legal.
Caffeine affects almost every organ system, the most obvious being the central nervous system. This stimulant increases alertness, reduces perceived effort during exercise, and decreases reaction time. At high doses (more than 15 mg/kg body weight), caffeine can also produce bradycardia, hypertension, nervousness, irritability, insomnia, and gastrointestinal distress. Many studies indicate that ingestion of caffeine can improve endurance capacity by as much as 20 to 50 percent in trained athletes engaged in moderate exercise. There are several mechanisms proposed for caffeine’s effects; it appears that increased fat utilization and glucose sparing occur only in the first half hour of high-output exercise, but that’s the most critical time. The overall caffeine benefit continues for a few hours at least. The effective amount is 3 to 9 mg/kg of body weight consumed 1 or 2 hours before exercise; this amounts to about 3 or 4 cups of strong coffee, although pills are used in tests because of interference from other compounds in coffee (drugstore caffeine pills contain 100 or 200 mg). People who regularly consume caffeinated drinks appear to experience much smaller ergogenic benefits from caffeine; the recommendation for them is to desist in caffeine consumption for a few weeks prior to the outing where they hope to enjoy its benefits. I’ve never observed this recommendation actually being practiced by coffee lovers. Although concern has been raised that consuming caffeine, a diuretic, may contribute to dehydration, the most recent studies show this doesn’t occur during exercise. Side effects, particularly at doses above 6 mg/kg, include headache and insomnia (not to mention abdominal cramps and diarrhea), so use of caffeine by acclimating mountaineers may augment the symptoms of altitude illness.
There’s a great deal of excitement about creatine among strength athletes and body builders because of studies that show it increases muscle growth in the course of strength training. Recent studies have questioned whether all the benefits seen are really muscle growth or are mainly increases in extracellular water that looks like muscle because of the indirect means of measurement. Numerous performance tests have shown that creatine supplementation is safe, expensive, and beneficial for sprinters and athletes whose sports involve cycles of sprinting and jogging, such as soccer and perhaps climbing. Studies evaluating creatine for benefits in endurance exercise are mixed, with pure endurance performance apparently unaffected or even slightly diminished due to the weight gain creatine causes. Endurance athletes may nevertheless benefit in that creatine appears to aid carbo loading, and taking creatine and carbohydrates simultaneously has been shown to optimize both creatine loading and carbohydrate loading. Most endurance athletes also perform interval training, which creatine might help, and mountaineers frequently practice rock climbing where creatine would aid in specific muscle development and improved strength training adaptation.
The typical creatine-loading protocol is to consume 20 grams of creatine monohydrate (the phosphate form is poorly absorbed) each day in four doses of 5 grams spread throughout the day during the first 5 to 7 days—the “loading phase.” Thereafter, during the “maintenance phase,” only one dose of 2 to 5 grams is needed each day, as any additional creatine is excreted in the urine. Other protocols of 3 grams daily for a month have been found to be comparably effective.
Hydroxy methyl butyrate is a natural metabolite of leucine; about 5 percent of the leucine in your body is converted to HMB each day (about 0.2 to 0.4 g of HMB). Supplementing with 1.5 to 3 grams per day of calcium hydroxymethylbutyrate has typically been reported to increase muscle mass and strength in untrained or elderly subjects initiating training; it doesn’t appear to offer benefits to endurance athletes except perhaps to slightly delay onset of the lactate threshold or mitigate the catabolic effects of prolonged exercise. Gains in muscle mass are typically 1 to 2 pounds greater than controls during 3 to 6 weeks of training. HMB has a half-life of 2 to 3 hours after ingestion, so vendors recommend it be taken in several divided doses throughout the day (for example, 1 gram of HMB 3 times daily). Current research suggests that HMB may also enhance the benefits of creatine supplementation. Creatine worked about three times as well as HMB in increasing lean body mass during progressive resistance training, but the combo was almost twice as effective as that. In these studies the doses were 20 grams of creatine per day for a week, followed by two weeks at 10 grams per day, with 3 grams of HMB taken every day. Use of HMB as a supplement is heavily patented by Iowa State University, and all genuine forms must bear the U.S. Patent number 5,348,979.
That’s it. If your favorite supplement didn’t make the cut, sorry. At this time only these four have incontrovertible scientific backing for ergogenic benefits, though there are many other promising possibilities that may or may not eventually prove worthy of the claims that suppliers are making based on anecdotal evidence or studies of rats. Or maybe you’d prefer to spend your money and rely on the placebo effect.
Just what kind of vegetarian you are has a big impact on how difficult it will be for you to maintain good nutrition under the demands of strenuous activity at altitude. Little of what I’ve covered precludes ovo-lactarians; they’ll just have to be more deliberate than omnivores. Vegans, however, will have special difficulties getting the calories they need without becoming overloaded with fiber. Getting the necessary amino acids, particularly branched chain amino acids, will be especially challenging. The best strategy is to eat unprocessed grains and legumes with complementary protein compositions, the best-known combination being rice and beans. Tofu provides high-quality protein and other valuable nutrients, but it’s comparatively heavy. Vegans may have to raise their total protein intake to compensate for incomplete digestion—not easy given the problem of appetite loss at altitude. If you’re eating a vegetarian diet that consists primarily of grains, fruits, and vegetables, you’re probably eating an unbalanced diet that will adversely impact performance at altitude. Cooking times for vegetarian foods are apt to be long, so emphasize precooked, dried meals and carefully calculate fuel consumption. Vegetarians are often at risk of low vitamin B-12, riboflavin, zinc, and calcium, stores of which are stressed by mountaineering. Iron is less available from vegetable sources, and some common vegetables actually lower its bioavailability. If you’ve chosen vegetarianism partly as an aid to weight control, you’ll need to be especially attentive to nutrition. Take on the demands of serious mountaineering in small steps and monitor your body composition as you do. That’s good advice for everyone.