Diet for High Mileage Long Hikes

[paul johnson]

Richard, you’ve sure given us some great posts which are very informative and useful. I don’t feel qualified to respond however. I’m certainly no expert at any rate. Let’s see how Mr. Brissey responds, I’m sure that we both (definitely me at least) will learn something from him. To be honest, my real intense physical training was 25-35yrs ago. To my knowledge, muscle and exercise physiology was just starting to become real sciences (outside of the Soviet Block anyways). While most of the theory is still valid, most of the research that I’m familiar with might be outdated by this time. Besides, personally, I never paid too much attention to this type of food breakdown. I just ate a lot of protein, carbs, and fats – a bunch from high protein milk shakes (casein/protein powder additives) with raw eggs either mixed in or in a glass with the milk shake as a “chaser” (never contracted salmonella from the raw eggs).

[Anonymous]

40/30/30 is a good all around setup for active individuals (carbs/prot/fat)

If doing moderate intensity you can adjust to more 50/20/30 or 50/15/35, and many triathletes will do this when approaching race season since this usually corresponds with increased mileage.

Fat is great for calories, but you have enough stored on your body for many days of sustenance. So consuming massive quantities is gonna put a strain on your circulatory and digestive systems. As it’s been heard, “fat burns in a carbohydrate flame,” so don’t expect for your body to be a fat burning machine.

Long-distance athletes spend many hours “base-training” (approx sub-130bpm) to acclimitize their body to maximize usage from oxygen, fat, and glycogen in the body. At this lvl 1/2 exertion you’re burning fat/carbs/protein proportionately.

At higher bpm’s your body begins to depend more upon glycogen stored in the muscles/liver and that provided by carbohydrate consumption (usually in the form of high-GI sugar). Less fat is burned at these levels although you can increase the amount burned by base training at a lower level of exertion. On average, most people’s muscles have enough stored for approx 50-80 mins of moderate exertion, beyond that long chains of glycogen (short and easily used ones already in the muscle) from the liver must be broken down, which will provide bodily fuel for several hours. If you haven’t been topping off the tank before, during, and after all this work, you’re body will go catabolic aka eat itself…
This is why it’s a good idea to replenish carbohydrate stores with approx a 7-9% solution (aka gatorade). It’s also shown that a few grams of protein consumed with that carbo beverage will delay muscle fatigue/soreness and prolong endurance.

Sorry so long, but that’s just a lil bit of the triathletes skinny on what your insulin delivery system is doing with glycogen and carbs.

Also let’s not forget MCT’s–Medium chain Triglycerides help delay glycogen depletion in the body prolonging endurance.

–nutrition and how many cals per hour you can tolerate and whether it be a solid, gel, or liquid form is an important aspect to long-distance ventures.

Personally, I take a few aminos, endurolytes or sea salt, and gatorade. Mainly because it’s readily available. If I’m doing an event, I like the taste of champion nutrition’s carbo bev and met endurance (pre-event meal replacement w/ mct’s)

Mct’s naturally occur in coconut oil.

we can go on 4ever with this stuff, just ask any endurance athlete about nutrition plans, but ultimately whatever tastes good to you when you’re all hot and sweaty is the best choice…so better go get hot and sweaty and see what looks good in your snack pan…

[paul johnson]

>>”At higher bpm’s your body begins to depend more upon glycogen stored in the muscles/liver and that provided by carbohydrate consumption (usually in the form of high-GI sugar). Less fat is burned at these levels” [emphasis mine]

Good post. Just one question for clarification:
Are you trying to say less fat is burned at higher workout intensities, or are you saying that a lower percentage of the calories burned come from fat as the energy source. I think you meant the portion of energy provided by fat is now a lower percentage of the overall energy sources being utilized at a given point in time at high %VO2-max. This is what I recall learning many moons ago. Not trying to be nitpicky here. Not everyone reading this Thread has your level of understanding of human phys. Can you clarify please. Many thanks.

[Eric Noble]

Thanks Bill, for all the great information you provided in response to my questions! I went to the Ensure web site looking for the dry version of Ensure but did not see it. Is it something that is available to the general public? You mentioned your dietitians help in procuring it. Is this required?

Ensure is intriguing to me, but the liquid form seems problematic for backpacking because of the weight. By the way, how well does it keep? Last year I was reading about the Race Across America that Randy mentioned in his post above, and Ensure Plus seems to be the diet of choice. Here is the link: http://www.ultracycling.com/nutrition/what_raam_riders_eat.html.

[Bill Fornshell]

Eric, They call it Powder and it is hard to find.

Try Here

I have had the Ensure Plus and a lot of something called ProSure (another Ensure product) that might be even better for you than Ensure Plus. The ProSure says it “Helps Build Muscle & Promotes Weight Gain, Has a Unique Blend of an Omega-3 Fatty Acid (eicosapentaenoic acid 1g/8 fl oz)& Protein (17g/8 fl oz) etc. I took this stuff while I was in my treatment program. It helped me regain some of my weight after each Chemo treatment. It is 300 calories per 8 fl oz can. I went through about 200 cans of this stuff at about 4 cans a day. It comes in flavor’s and the banana was the best. This stuff is made for people on Radiation and Chemo treatment.

I have been on a liquid diet for 10 months almost a 100% if anyone has any questions about how my body has adjusted to it.

[Anonymous]

paul. yes, higher intensities are correlated with less fat burned and more glycogen/carbohydrage usage.
However, the “percentage” used will be based on individual fitness.

You can be sure that athletes like Lance Armstrong will burn more fat and less glycogen than the average person pedaling at 20mph on the bike. So his percentage will probably be higher than the average because he has trained his low bpm fat burning aerobic engine. This is the primary engine used in long-term events, power output is still important in overall performance, but “slow and steady, wins the race.” And with all endurance sports the “key” workout that you always try to get is the long workout aka 1 to 3-5 hours, generally speaking. This raises your overall aerobic capacity, mitochondrial stores (energy stores on the cellular level), and gives increased capillarization (better delivery/disposal in the body).

All of these adaptations lead to more efficient exchange of oxygen and energy in the body. In general, to burn fat, keep the pace “easy” and go for a long time. Some other time in the week, do a shorter workout consisting of hills or intervals–thereby raising your ability to tolerate working out at or near your LT-lactate threshold. But for long distance sports, pushing at that level is counter productive and will cause you to crash and burn…

once again long but–this is getting me hyped for ironman..and the trail

[Stephen Eggleston]

(sorry to go a bit off topic here folks)

Jim,

Basically cookies, granola bars and goo balls are homemade energy bars. I have read one historical account of roman soldiers in which their daily marching rations were described as two balls made of honey, sesame and an unspecified herb.(poor guys!)

The point is to make compact and nutrient dense food with the desired amounts of carbs, protein and fat that tastes super yummy. I’m not a recipe person(I tend to improvise), but you can take any cookie recipe and adapt it. Substitute whole grain flours for white flour or even add some Nutribiotic rice protein powder to the flour. By using a mixture of whole grain flours you can increase the protein content of the cookies. Also sub whole sugars like sucanat for white sugar. Sub butter or unrefined oils for low quality oils like wesson corn oil. Add nuts, oats, dried fruits, chocolate, expresso beans etc.

Another option is to make a raw version. Mash some dates or other dried fruits and mix with crushed or soaked nuts, almond butter, peanut butter or tahini. Add some honey. You can also add chocolate chips, quick oats or other goodies. Get the right consistency, make little bars or balls and then roll them in some quick oats or oat flour.

[Randy Brissey]

I have found the correlation between cycling and backpacking close in many areas…………

It has been in my experience that hiking along on reasonably flat terrain fairly difficult to raise the heartrate outside of the aerobic zone (around 65% max) except for elevation considerations….

For a couple of years I tried a “healthy” diet for competition but I would end up bonking after a couple hours because I never built up my anaerobic threshold where I could save glycogen until later. When I switched to a higher fat diet and adjusted my workout downward to a lower heartrate my threshold rose. I also discovered that a few other riders suffered from the same dilemma. We could not ingest enough carbs each day with feeling like we were forcing ourselves. Others could.

I discovered that as the days got longer (not more intense) my percentage of fat in the diet increased. We trained our bodies to glycogen spare and utilize the fat.

As someone has already alluded to it is “get the fires going with the carbs and feed fat to the hot fire”. We would eat cereals and outmeal at breakfast before a heavier meal after a couple hours.

The problem that I look at with 40 mile days for 20 days is weight.
Body fat is 3500 calories/pound
Dietary fat is 4000 calories a pound
Carbs and proteins are 1800 calories a pound

Some of the research says that for very highly trained individuals you can lose up to 2 1/2 pounds a weeks without muscle loss….say 9000 calories.

4000 calories a day = over 2 pounds of carbs or around 45 pounds for a trip or
1 pound of fat/day = 20 pounds fat for the trip

I remember reading about pemmican……..

I think also a question that needs to be asked is “In what shape do you want to finish the hike?”

Maybe at this point some graph paper would be handy!

Maximum intended body fat loss along with various ratios of fat/carb (since protein seems to be a fairly constant) against a maximum food load……….

I like this project!!! Randy

PS You can satisfy all of the people some of the time and some of the people all of the time, but you still can’t fool mother nature.

[Anonymous]

This is one real interesting and informative thread. A fat loaded diet, if one can tolerate it, seems to me to be best suited to this type of hike. I am assuming a high level of cardio-vascular fitness, which means low bpm which means high ratio of fat metabolized. The obvious advantage of a fat diet is lower weight which means longer distance travelled per calorie. A potential problem is that fat takes longer to become available for energy production and, in the process(correct me if I’m wrong here) diverts blood from the working(legs primarily) muscles to the muscles of the stomach/small intestine. So, it seems to me the timing of fat intake is important. My own personal preference has been to emphasize carbs(not to the exclusion of fat/protein) from breakfast until dinner and then load up on nuts, chocolate, etc at dinner and let the stomach do its thing while the legs are resting and replenishing their glycogen stores. Most of my experience with this has been at relatively high elevations(10,000 on up to ~20,000), so I’m not sure how this relates to Ryan’s expedition. I also bulk up ~6 pounds(on a 137# frame) in the 2-3 weeks preceding a relatively long hike of ~2 weeks and come out the other end weighing about 132. Accelerade and Endurox are also part of my routine for the first couple of days. Thereafter the fat heavy routine kicks in and the miles just seem to go by. One other thing that occurs to me: for a quick energy boost have you considered pure powdered glucose, Ryan? Especially for that “bonky” feeling when the brain is starting to bitch about not getting it’s share. Just some thoughts, obviously nothing scientific. Hope it helps a little.

[paul johnson]

I understand the intracellular changes in numbers of organelles and available enzymes. This is for both metabolic pathways.

Your reiteration, still doesn’t quite agree with what I had learned back in the 70’s.
I’m very interested in understanding what newer research has changed this theory.

Keeping it basic for all to follow, here’s the way it went back then:

Fats and carbs are burned in varying proportions in the cells via aerobic and anaerobic pathways. As work output went up, energy needed to be burned at a higher rate. There is only so much oxygen available, so after some point, the extra energy had to come from carbs. Before that point was reached, both fats and carbs contributed to the energy requirements of the muscles. The overall energy requirements increased for both fats and carbs, but the percentage of each burned relative to the other changed with carbs becoming a progressively greater proportion.

The amount of fat utilized increased with the HR (up to a certain point) based upon available O2, but it’s percentage relative to carbs decreased. In fact, what I had learned years ago was the “myth” of the so-called “fat burning” zone.

Higher work levels actually burned more fat (en toto) subject to oxygen availability, but at a lower percentage relative to the carbs. To further clarify, what I had been taught, your Lance example would be because of two factors, the reasons you stated, a trained athelete vs. an untrained individual (diffs in blood cells density and hemoglobin, and the intracellular “engines” = greater capability and efficiency in processing both energy sources), but also because for the same effort his heart rate will be lower, since Lance is more efficient. The lower heart rate and greater VO2-max allowed greater utilization of fats.

To answer my question, we should really be comparing one person against himself, not against another person. The point being if a person exercises at 65% MHR, he burns x amount of fat and y amount of carbs over a given period of fixed intensity work. Now, without any appreciable further training effect, for example a workout two days later, exercising at 85% MHR, x+m fat is burned (more fat en toto), but y+n carbs are burned, where n >> m (n is much greater than m, which increases slightly). Therefore, while fat “burned” en toto increases slightly for the same period of time of exercise at a higher intensity, the percentage of total energy utilized coming from fat has dropped since much more carbs are being utilized. This was called the myth of the “fat burning” zone at that time. The theory that I had learned was that you would always, up to a certain point, burn more fat en toto as work output went up, but that the fat would be a steadily decreasing percentage of the overall energy output.

Again, can you describe the research that was performed that changed the paradigm that I had learned.

[paul johnson]

Randy,

Many years ago, the thought was to use interval training as a means of achieving the effect you describe. Periodically, interval training would be inserted after some period of time of regular training. Research, at the time, indicated that it was even more effective than consistent training at very high HR to increase the anaerobic threshold. I’m sure that you understand the rational for doing so – the thought being that the body over-compensates due to the “surprise”, so to speak, of the varying workload associated with interval training. The body can’t anticipate certain requirements and so, overcompensates. The theory behind this interval practice was similar to another practice that crept into vogue at that time, viz. carbo-loading. This effect is, in one sense, similar to what happens as the body reacts to fasting, by “holding onto” more fat, and catabolizing more muscle protein in a survival effect. The human body seems to behave/overreact in this way on a number of fronts.

If I understand you correctly, which I may not, it sounds like you’re saying that more recent research has proven the interval training approach to be either unsound, invalid, serving a different purpose, or less effective than the method you describe. Would you mind educating me on this pont please?

[paul johnson]

On a somewhat related note which might be of interest to some (if not, don’t bother to read):

Here are some Muscle/Exercise Phys. “numbers” and info. I’d appreciate feedback from those with more up to date info on whether this info is still considered valid based upon more up to date research.

Depending upon the level of physical exertion and your body’s related heart rate, your muscles will burn “fuels” in different ratios – subject to the availability of oxygen being transported into muscle cells. More specifically the hiker is engaged in a long duration moderate intensity form of exercise. So, a “ballpark”/approximate breakdown of the “fuels” utilized is normally as follows:

25% each from:
— fat stored as triglycerides within the muscle
— carbohydrate stored as the starch glycogen within the muscle
— glucose released into the bloodstream from the liver.
— fat coming from diet or released from storage in adipose tissue

if at all possible, our bodies don’t like to exclusively use just energy sources stored in the muscles, thereby depleting/exhausting them completely, just in case some sort of “surpreme” exertion is attempted/required. our bodies don’t want to let us down if at all possible.

I think that these percents are a bit off in this simplified example, and that often more fat is burned due to the lower levels of exertion by the hiker on level terrain. Do those with more up to date info disagree? Is any of this still valid? I think it’s a simplification, in terms of the percentages given, of what actually happens.

as exercise intensity increases beyond a certain level, approx. the same amount (in an absolute sense) of fat is “burned” (absolute amount depends upon “cardio” conditioning which is related to the amount of oxygen available in the red corpuscles in the blood and intracellular training benefits to utilize oxygen, fats, and carbs in the little cellular “engines”), and any increased energy demand is met by burning more carbohydrate, so the ratio of carbohydrate to fat increases.

a typical value one often reads, for a well conditioned long distance hiker, for depletion of stored glycogen reserves, is approx. 6hrs. i’ve never been able to determine a continuous heart rate associated with this 6hr figure. my guess might be ~60% of the so-called age-adjusted-maximal-heart-rate, but this is just a guess. frequent “snacking” while hiking is a good strategy for preventing depletion and replenishing these energy stores.

the talk is mainly about carbs and fats as proteins are not burned as fuel, per se. they undergo a catabolic pathway beginning with deamination, IIRC, and are converted to simpler carbon compounds via different pathways to produce glucose or ATP – my memory is not real clear on this, however. as far as storage of amino acids/protein i don’t recall this occurring. i do remember that when an amino acid deficiency does occur, the body in order to utilize the other amino acids to allow protein synthesis to continue will catabolize labile body proteins, including plasma albumin, and muscle tissue in order to permit protein synthesis to continue. to the best of my recollection, amino acids are not stored. any unused protein/amino acids are deaminated and then oxidized via both gluocse or fat metabolic pathways and stored as glycogen or fat, respectively. the excess nitrogenous waste produced by these pathways is excreted in the urine as either ammonia or urea. once stored as glycogen or fat, they are later used as fuel/energy, not building blocks for protein. when protein intake is inadequate or specific essential amino acids lacking (those that cannot be metabolized by the human body from other sources, but must be ingested) the body will then have to catabolize (“break down”) certain other protein sources already present in the human body to supply the missing amino acids. depending upon the degree to which this needs to be done, there can be serious side effects from this. an increase in urinary nitrogen can be caused by insufficient protein intake and is looked for as an indication of this condition. (at least that’s how i recall it, but it’s been quite a while, so please verify this).

Also, I’m feeling like perhaps, due to all involved maintaining some semblence of brevity in their posts on a complex subject (this one being an exception), that, at times, different points are being emphasized and the precise topic is not covered in each post (e.g. the example of Lance, and my response – maybe we weren’t on the exact wavelength, hence some minor discrepancies).

This sure is a very interesting subject though – to me at least. Sorry, I can’t contribute better info, it’s been 30-35yrs since I’ve had to think about this stuff. Hope our Phys. Prof. can shed better light and correct any errors I may have introduced. I think at this point, other than asking questions, I’m all “Posted-out”.

[Anonymous]

http://www.ultracycling.com/nutrition/calories.html

paul check out this furthered link posted by someone else. Half way down are “general” economies for CHO/fat consumption for various Heartrates.

Approximate Sources of Energy While Riding
% of VO2 max CHO/Fat
20-50% about 50/50
60% about 60/40
70% about 70/30
80% about 80/20
90% 90-100% CHO.

Yes we skipped over the ATP/CP cycles, glycemic indexes of sugars, but there are whole sites dedicated to this. And ultimately, tolerance to different foods during physical activity is a very individual thing.

As a triathlete, I know that my intake for long events (6-12 hours) is about 200 cals an hour usually in the form of liquids and the occassional gel. I also will consume a clif bar or banana to slow gastric emptying. Simliarly, I shoot for about 40-48oz of liquid per hour usually in the form of a carbo bev.

If it’s going to be hotter, I have to train my body to process more through the heat acclimitization and copious amounts of water w/ sea salt.

Not that anyone cares about what I’m taking down in a race but i wanted to give an example. For most people, 100-400 cals an hour is common–just have to find what works without making you sick. This way you never fully tap your glycogen stores and can feel recovered the following day.

If you wait to replenish and do not find out your tolerances per hour and how much liquid you require in various climates, you will eventually bonk especially if it’s a multi-day event.

Just a tip to RJ about endurox and accelerade–great products! but I think you’ll find that they are too sweet on the palate for multi-day use. Perpet is a nice one, but gives me gas.

Honestly, a nice flask with your favorite gel or HONEY is great for calories on the go. Just don’t rot your teeth and drink plenty of water.

thanks for the forum

[paul johnson]

Thanks alot for the post. Good info. Really appreciate you taking the time to post.

I still carry a little squeeze “Honey Bee” plastic container. Thought maybe it was out of vogue or frowned upon by “modern” research. Glad to hear I’m still doing something right. I find that, depending upon how much honey I’ve “squeezed down” at one time, my body naturally wants ~250ml, more or less, of water as a “chaser”.

[Randy Brissey]

Intervals are a great method for training for the sport you are in. Great for cycling because of the change of speeds but not so great for the triathletes because the goal is to step up to the anaerobic threshold line but not step over.

Lance and his team of trainers altered the landscape of training by pushing the concept of anaerobic threshold up against the VO2 max. But then again mr. Armstrong is a genetic freak (his ability to handle lactic acid). The other situation is that Lance raced so little that he did not have to keep recovering from race after race of anaerobic efforts.
The key to this whole mess was (is) the introduction of the power meter. Instead of just measuring your effort against a tachometer (HR) you now can see what is needed to compete (Watts). With the powermeters you can step right up the edge but not fall over the lip.

For long distance hiking (along with Race across America) the concept is to stay just below that point where you deplete your high octane fuel (glycogen).

Backpacking for me was a no-trainer. Because I cycled (and lifted weights) all I needed to do was to mix in some very fast hiking in hills to get the joints used to the stress on the knees, calves and ankles. I had even been lucky enough to have walked off the trail one day and entered a bicycle race the next with no adverse effects.

For me I love cycling and I love backpacking but I look at hiking like I do weightlifting, something that I need to do to ensure my pleasure at what I like to do.

Randy

[Randy Brissey]

Paul,

Training at a high heart rate ends up being counter-productive (I was teaching this subject last week).

I usually relate to training in 4 heartrate zones. The first (lowest) I call the fat burning zone……wightloss without cardiovascular training. The second I call the green zone…..aerobic training……being able to carry on a conversation without gasping. THe third I call the blue zone (place where competition levels are found) and the last the red zone…..intervals-hell!

As long as a person stayed in the green zone fitness increased until to reach that theoretical maximum. The third level of HR (blue zone) which is around the AT is a problem. It is too hard to boosting aerobic effciency. It is difficult to recover from an extended workout here but at the same time it is too easy for full interval effects.

The problem when I deal with student jocks is that the easy days are too hard and the hard days are too easy. Students are working too hard and they burnout on their sports.

I remember an important point that a Race Across America competitor relayed to me. He said that the most important place to save and utilize energy stores were for climbing hills (passes). Here the differences between fitnesses of competitors is magnified the most.

Randy

[cary bertoncini]

type training than was considered the norm?

I read somewhere that during off season he did considerable volumes (more than most) of slower paced cycling, rather than a lot of VO2 stuff.

Was he doing extreme periodization? Lotsa lotsa base work, then lotsa V02 stuff closer to race time?

[Richard Nisley]

In reference to table (http://www.ultracycling.com/nutrition/calories.html) graciously provided by Anonymous, I have two comments about the 20-50% VO2 max range ratio of CHO/fat burned.

1)For a credible cycling reference, Chris Carmichael’s (Lance Armstrong’s coach) book titled, “Food for Fitness”, page 29. He says, “The numbers presented below are approximate values and ranges based on what I have seen in more than 15 years of coaching athletes…”.His numbers match the Ultracycling article except that he broke the VO2 max 20-50% range into two segments of 20-35% and 35-50%. I have added his ratio numbers below the Ultracycling table numbers for 20-50%.

Approximate Sources of Energy While Riding
% of VO2 max CHO/Fat
20-50% about 50/50

20-35% about 30/70
35-50% about 50/50

60% about 60/40
70% about 70/30
80% about 80/20
90% 90-100% CHO.

2) In my initial post on this subject, I estimated that Ryan could accomplish his distance and time goals while maintaining a hiking pace of about 5 METs. At 5 METS his % of max heart rate would in the range of 60%. This equates to a VO2 max number of approximately 35%. VO2 max is correlated with the % of max heart by the formula %VO2 Max = (%MHR – 37) / .64. By staying at or below this pace, he will primarily burn fat rather than CHO. This has the benefits that his pack weight would be the lowest possible, since calorie density is optimized, and he will optimally sustain his body’s needs. Randy Brissey clearly pointed out the dramatic difference in Ryan’s potential pack weight using this approach.

[Ryan Jordan]

Re-read all the posts, in the context of some other research I’ve been reading.

Specifically related to the role of carbs, fat, and protein during exercise.

It seems to me that the first few hours of exercise rely primarily upon glycogen stores in the muscles for energy. Supplementing these stores (since utilization of them is not 100%) with a small amount of complex carbs with a high glycemic index (so they are utilized rapidly) is the way to go.

I’ve also found that complex carbs can be absorbed at a higher caloric density than simple carbs. It seems that you can only supply your body with so much in the way of simple sugars. It simply cannot process them fast enough, and eventually, leads to gastric distress if you try to overfuel yourself with higher concentrations of them. So if you’re bonking, eating simple sugars will raise your blood sugar, but will also cause it to dive when it’s done. Seems like the ideal energy gel should have complex carbs with a high glycemic index, to address the bonk. Better: a steady diet of complex carbs to avoid the whole situation?

As for fat “burning” during exercise, I found no evidence that you gained much energy by, say, just eating butter. Yes, you were burning fat, but it seems that the fat being burned comes primarily from your fat stores, not the fat you ingest. And this is where I am confused, so a question:

Q: is there immediate benefit from eating fatty foods, in terms of grabbing energy from them during active exercise at say, 50-65% of VO2max?

Where it really gets interesting from a long distance perspective is what to do immediately upon arrival to camp in terms of nutrition. Replenishing glycogen stores when the enzymatic engine for doing so is cranked up seems vital. I’ve read that the “window” for doing this ranges anywhere from 30 minutes to 2 hours and seems to be somewhat dependent on the amount of excess post-exercise oxygen that you’ve accumulated (EPOC, which is a function of intensity and duration). Glycogen seems best replenished (without causing gastric distress) by – again – complex carbs with a high glycemic index. Of course, some protein is important in this window as well to replenish amino acids that were cannibalized during the activity.

Finally, the name of this game is your ability to stave off the inevitable degradation of your body for as long as possible. In an “event” like this, you are probably entering Day 0 at your peak, and it’s all downhill from there.

There is absolutely no evidence that an unsupported long distance event of any length near the limits of one’s endurance capacity can be anything but a degradative effort.

Which again, begs the question.

How far can a hiker go, unsupported?

[Frank Ramos]

If my memory of physiology is correct, the brain runs only on glucose from the bloodstream, which must be supplied by the liver. If the liver runs out of glycogen stores, then it has to begin converting protein to glucose. At first, the liver will use dietary protein for this. I believe the liver stores about 3 lbs of dietary protein that is normally intended for use by the cells, but which can be converted to glucose if necessary. Once that protein is exhausted, the body must begin destroying muscles. The brain must get glucose regardless of the expense to the rest of the body. I forget exactly how many calories of glucose the brain needs per day. Probably about 600, which is enormous in comparison with other animals.

In order to avoid destroying muscle too fast, it is thus essential both to walk slow and thus allow the muscles to burn mostly fat, but also to eat enough carbohydrates and proteins to provide the brain with glucose.

I would guess that a half-pound of oats per day would be sufficient to prevent rapid loss of muscle, but a pound a day would be much better. A normal man weighing 165 lbs, and neither very fat nor very lean, should be able to go at least a couple of months on this amount of food, slowly but surely losing all his fat and some of his muscle. A pound of oats would provide about 1700 calories, mostly complex carbs but also a good amount of protein and fat and also some fiber. Bulgar wheat, buckwheat kasha, rolled wheat and rolled rye are other good choices from the natural foods stores. All of these grains can be eaten uncooked. If you are really planning to hike in Alaska in the early summer, you will definitely want to be able to prepare food inside your tent to avoid bugs, and so uncooked food is a good way to go. Uncooked grains have very little smell and so won’t attract bears. Contrast with butter, which even I can smell from a block away once it starts to warm up. I would imagine a bear could smell warm butter from several miles downwind. And don’t forget some light salt (50/50 mixture of potassium chloride and sodium chloride) and vitamin pills.

And another thing. Ignore all this idiotic advice about variety and palatability. You want your food to be as boring as possible so you aren’t tempted to overeat. Boring, but not disgusting. Oats with a little salt is just that. Whatever you do, don’t bring along raisins and nuts and other stuff to make the oats taste better, because then you will have a very hard time controlling yourself from eating more than a pound a day, so you will run out sooner. And once you run out of food, the only way to supply the brain with glucose is by destroying muscle.

I have no evidence for the claim about being able to walk for months on just a pound of oatmeal a day, other than my undrestanding of what humans have traditionally endured. Going an entire winter on a small amount of wheat per day, and being forced to plow the soil and do other hard work with this tiny amount of fuel, is actually a very common story in human history.

[Richard Nisley]

The answer to your first question is No, “there is no benefit from eating fatty foods, in terms of grabbing energy from them during active exercise at say, 50-65% of VO2max?”

The answer to your second question, “How far can a hiker go, unsupported?”, is 643 miles carrying 40 lbs of the correct food at 44% of VO2 max.

Your body can only store about 1,500 – 2,000 C of CHO derived energy unlike fat energy which is by comparison vast. After you consume this limited CHO store you will bonk.

As an example, I am 62 yrs old, weigh 190 lbs, and have a VO2 max of 45. At a 50% of VO2 max rate, I am burning 570 C per hour and approximately 50% of the energy is coming form CHO or 285 C/hr. At this pace my CHO store will last between 5.2 and 7 hours and then I will bonk.

At a 65% of VO2 max rate, I am burning 741 C per hour and approximately 70% of the energy is coming form CHO or 519 C/hr. At this pace my CHO store will last between 2.9 and 3.9 hours and then I will bonk.

Your body can only metabolize about 350 C/hr when exercising heavily and so also needs to be factored into your exercise pace and CHO replenishment strategy.

If you stay at or below heart rate zone 2, which equates to a VO max limit of 44%, for maximum distance efficiency you could backpack up to 643 miles unsupported. At least that was what my back of the envelope calculations just yielded. Of course this is like your winter camping trip under 5 lbs equipment request post. We would rather you test the limits of survivability than us! <grin>

Using my vital statistics as an example, I consume about 500 C/h at 44% of VO2 max. 12 hours a day hiking and 2 hours of camp chores would require 7,000 activity class Cs per day. My daily basal metabolic rate is 1,730 C plus an additional 10% of the total energy Calories will be consumed in digestion (thermic processes) yielding a daily total of 9,567 for 40 miles of cross country hiking.

The daily fuel requirement, to support this activity for a sustained period, is approximately 65% fat (6,219 C = 1.8 lbs of stored fat or 1.6 lbs of dietary fat), 25% dietary CHO (2,392 C = 1.3 lb a day), and 10% dietary protein (957 C = .53 lb per day).

Up to a maximum of 10% of the average persons body weight can be dropped on a long backpacking trip without any health consequences. So for me, 19 lbs * 3,500 C = 66,500 C would be planned to be taken from my stored fat bank. At 1.8 lbs of fat required per day, I could internally supply this requirement for 19 / 1.8 = 10.6 days.

The minimum daily food value that needed to be consumed would be 1.3 CHO + .53 Prot = 1.83 lb per day for the first 10.6 days or 10.6 * 40 = 422 miles. The total food weight for this segment would be 10.6 * 1.83 = 21 lbs. After that then the daily food value necessary would be 1.6 (Dietary Fat) + 1.3 (Dietary CHO) + .53 (Dietary Prot) = 3.43 lbs per day. Assuming 40 lbs of food would be the practical limit to carry I could go another (40 -21) / 3.43 = 5.5 days, 5.5 days * 40 = 221.6 miles.

Ah ha! Ryan is a slacker! Only going 400 miles cross country when he could actually go 422 + 221.6 = 643 miles. Of course if my calculations are wrong he might starve. Arrg… Ryan be sure and double check my math and logic before trying this.

In summary, a 28% increase, from 400 miles to 643 miles is feasible by changing the VO2 max zone for your hike from your planned 50 – 65% to an average of 44%.

In my original 2/16/06 16:27:44 MST post I pointed out that you should be able to achieve your time and distance goals with an average 5 MET expenditure. My above fuel recommendation, for a 44% of VO2 max pace, conservatively yields a 7 MET allocation; 502 Cal/hr (expenditure) / 72.1 (BMR) = 7 (METs). As they say in the car mileage advertisements, “Your mileage may vary”.

[Michael Wands]

A question for Frank Ramos:

How do you prepare these no-cook oats that you carry? My rabbits love rolled oats, but I’ve never really considered eating them myself.

How about the Carb grams per serving? I got a big surprise for my 50th. I was diagnosed with Type 1 Diabetes!!! This is no big deal, but it is inconvient. I used to have the option of fasting on weekend hikes, but now I have to keep my blood glucose level in a certain range.

[Kevin Sawchuk]

At nearly any pace short of running you will be burning mostly fat–especially if you’ve trained at a similar pace. Even a 150# person who is very lean (5% body fat) has 7-8# of fat which will provide 28,000C–enough to last about 6-7 days if taken with some carbohydrate. After that you’ll start burning more muscle unless caloric needs are more fully met. The story doesn’t stop there: You need carbohydrate to burn this fat. When you’re burning endogenous (body) fat in the first few days a small amount of carbohydrate –100-300 C/hour–is probably enough. You can’t store much carbohydrate and fat can’t be converted to carbohydrate.

After the first few days you’ll need more calories including a good mix of fat, carbohydrate, and protein. At this point you should get close to as many calories as you need or your performance will suffer. It’s probably better to more evenly distribute you caloric intake than to wait to start eating until the 5th day. However if you’re only on a <7 day trip you may be able to scrimp a bit.

Liquids are easier to take than solids but on a long trip I find that variety really helps you keep up the calorie intake. I personally don’t think eating only cold meals is worth the weight savings–for me it’s just unappealing. I use a lot of drinks in the day (Balance, Acceleraid, Cytomax) but want a more solid meal (cooked) at night and some solid food in the daytime. This is a personal preference–if you can tolerate liquids for 20 days go for it!

[Frank Ramos]

How do you prepare these no-cook oats that you carry? My rabbits love rolled oats, but I’ve never really considered eating them myself.

You just pour some regular 5-minute rolled oats in a bowl with some water, and start eating them. You can also add salt, powdered milk and dried fruit to the mixture if you want. The body digests all this food just fine. 1-minute oats is also okay, though I prefer the texture of 5-minute oats. I would avoid instant oats since I don’t trust foods which have been highly processed.

You can do the same thing with bulgar wheat, buckwheat kasha and rolled wheat and rolled rye. Wheat is the most nutritious of the common grains, but I prefer the taste of oats. All these grains have essentially the same number of calories per pound (about 1700).

Couscous is another possibility, but a poor choice. Bulgar wheat is wheat berries which have been steamed until they burst open, then dried, and is thus the entire wheat berry. The similar-looking couscous is refined flour which has been rolled together into tiny pellets, then steamed to pre-cook it, then dried. Couscous has the same lack of fiber and minerals as white bread or white flour pasta.

Type I or Type II diabetes? Regardless, uncooked 5 minutes rolled oats has a lower glycemic index than cooked 5 minutes rolled oats, which in turn is less than 1-minute oats, which is less than instant oats. The lack of cooking and the texture of the 5-minutes oats seems to slow down the digestion, at least in my experience. I can eat a big bowl of uncooked oats without feeling any blood sugar surge. With couscous, on the other hand, I would feel a blood sugar surge.

[Bill Cooper]

Nisley’s prior post was fascinating. But I thought his estimate of 9,567 kcal per day was high, so I took a somewhat different approach with different assumptions to calculate Ryan’s energy requirements for a 40 mile day. Whallah! I came up with almost the same number. Ryan is going to be one tired dog!

BTW, an average hiker can use the this method to calculate -approximate- caloric needs for a hike. Guess-timates also work.

Nisley used MET values in his calculations. These are often used in population studies and provide a convenient shorthand for estimating caloric expenditures for different activities. Tables of MET values are available in texts and on the web; one extensive table is linked off this page: http://prevention.sph.sc.edu/tools/compendium.htm .

The values are derived from laboratory studies and inferences, but they’re only estimates for real world conditions which vary with body build, conditioning, environment, etc. A MET (Metabolic Equivalent) is defined as an energy expenditure of 1 kcal/kg/hour. This is roughly equivalent to the energy cost of sitting quietly, i.e., your approximate basal metabolic rate (BMR).

Since MET values for different activities include this 1 MET base, one should not add the day’s non-resting energy expenditures to the BMR, only the differences. In other words, an activity such as “walking 4 mph on level ground that uses ‘x’ METs” is actually using only an additional “x-1” METs over the BMR. So to calculate the day’s energy costs, take the basal metabolic expenditure and add the sum of the day’s activities each calculated at an adjusted rate.

Energy expenditure is correlated with body mass for most activities. Strictly speaking, you would plug in a different weight for camp chores than for when carrying a pack. So if Ryan himself weighs 170 pounds and started with a 50 lb pack (10 lb base load and 40 lbs of food), his exertion at the beginning of the hike would be based on a 220 lb weight. Assuming linear food consumption, we can use an average pack weight of 30 lbs and a total skin out weight of 200 lbs (nice round number) or 91 kg (not so nice).

On a side note, walking efficiency isn’t a flat curve, i.e., you typically expend more energy per mile the faster you walk (indeed, there’s only one physical activity that has a fairly flat efficiency curve and that’s running). If I remember correctly, the most energy efficient walking speed for a person of moderate build is somewhere around 2.2 mph. As a practical matter, the overall most efficient speed for a long distance hike is higher since there’s a daily basal metabolic cost just to be out there. It would be interesting to calculate some speed and consumption curves and see where they intersect and whether this method jives with the VO2 max calculations.

Finally, it takes “physical” work to lift an object against gravity (walking doesn’t do much work in the “physics” sense). Though my calculations may be off (correct me), it requires about 70 kcal to lift a 200 lb. body 1000 ft. If we assume 25% metabolic efficiency, that translates to 280 kcal of food needed per thousand feet of climb. (BTW, you don’t necessarily gain it back going down – steep descents are more energy expensive than walking flat but we’ll neglect downhills).

Assume Ryan covers half of a 40 mile day walking on fairly unobstructed surfaces and half the distance bushwacking (no stopping to swat mosquitoes!).

If Ryan averaged 3.5 mph on the unobstructed surfaces, the approximate MET value would be about 4. Let’s add an additional 1 MET since the surfaces aren’t smooth for a total of 5 METs. Ryan’s speed will fall while bushwacking but the work is harder. Let’s say he makes 2.5 mph (boy this dude’s working) and assume a 7 MET rate for those 20 miles. We don’t know where Ryan’s going but let’s assume 3500 vertical feet of climbing each day.

The calculations go as follows using MET rates corrected for the subsumed BMR, i.e., reduced by one:

Unobstructed walking:
20 miles at 3.5 mph = 5.7 hrs ; 4 kcal x 91 (kg) x 5.7 (hrs) = 2075 kcal

Bushwacking:
20 miles at 2.5 mph = 8.0 hrs ; 6 kcal x 91 (kg) x 8.0 (hrs) = 4368 kcal

Climbing:
3.5 (thousand ft) x 280 kcal = 980 kcal

Camp chores (housework):
(2.5 – 1) kcal x 77 (kg – no pack!) x 1.0 (hrs) = 115 kcal

Basal metabolism:
1750 kcal

Total: 9288 kcal

Ryan hopefully will take daily self portraits so we can see how haggard he gets!

[Author]

Posts