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Terry Dussault
Lets rely on science on 05/22/2006 08:22:40 MDT Print View

Early in the history of, an long article by Dr. Brenda L. Braaten available. The article was called “Pack Light, Eat Right”. Dr. Braaten is a Registered Dietician and holds a Ph.D. in Biochemical Nutrition from Tufts University.

1. In her article she correctly stated that “The Energy Machine is fueled by carbohydrate and fat.”
2. Endurance is most critically determined by maintaining carbohydrate/glycogen stores in muscles.
3. Fat and carbohydrate, not protein, are the preferred fuels for muscle.
4. GLYCOGEN is the first fuel to become depleted.
To avoid glycogen depletion, snack frequently (20-30 grams/hour) throughout the hike, and eat a high carbohydrate meal within an hour after quitting for the day.
DON'T eat a high sugar snack just before exercise, unless it is combined with other low sugar foods.

Jay McCombs
(jmccombs) - MLife

Locale: Southwest
Re: Lets rely on science on 05/22/2006 10:43:40 MDT Print View

All macronutrients (protein, carbs, fat) can be used as substrates for fuel and gluconeogenesis. Carbs and fat can't be used for substrates for new protein synthesis. Consequently I like higher protein intakes for all athletes. I did mean per lb. Lance wasn't in the same boat as Ryan. I'm working on the assumption that Ryan will be net hypocaloric if his energy expenditure is what people are estimating vs. his planned caloric intake (though I think there might be some overestimating going on). Endurance athletes are notoriously under-eaters of protein. If you under shoot the protein it could be detrimental. If you overshoot it can still be used as energy by converting it to pyruvate then acetyl CoA. Can't say the reverse about carbs and fats (get get amino acids out of them). Additionaly protein is essential in stimulating protein synthesis while insulin is only permissive/modulatory. They key is thinking what happens when you are isocaloric or hypercaloric vs. what happens when you are hypocaloric. If Ryan is determined to pack an amount of food that leaves him hypocaloric he can't follow the advice of traditional diet plans based on athletes eating a hyper or isocaloric diet.

The whole GI thing, sugar is evil thing, is an outdated concept. Its tough for nutrition oriented people to look beyond the single meal and think about the diet as a sum total of eating events. 10g of sugar holds the same amount of energy as 10g of brown rice carbohydrate. People don't get fat because of the food they chose but because of how much of the food they chose.

I would be far less concerned with meal to meal decisions. I would spend my time concentrating on getting a diet that has ample protein and calories in general and not limit myself to the simple/complex carb dogma as its tired and dated :)

If anyone is just convinced I'm FOS pick a topic and I'll provide you w/references.

John S.
(jshann) - F
Re: Re: Lets rely on science on 05/22/2006 12:30:03 MDT Print View

As far as protein goes, I'd shoot for 15% in my diet and try to get a complete protein in the food choices.

I'd like to see references stating that the simple/complex carb dogma is not valid for competitive athletes.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Lets Rely on Science on 05/22/2006 13:39:38 MDT Print View


If the diet is calorie sufficient, low exercise activity has little impact on protein requirement; a 1.0 gram/protein per kg/day is sufficient. However, most endurance athletes require more dietary protein intake for 3 reasons:

1. Insufficient carbohydrate calories to meet energy expense
2. Insufficient protein calories to meet energy expense
3. Exercise training expenditure increases 10-fold above resting state

Studies confirm that both endurance and strength training increase skeletal muscle protein synthesis (breakdown). Researchers using nitrogen balance measuring technique confirm protein requirements for endurance exercise is increased to between 1.2-1.4 g/kg bodyweight per day.


Jay McCombs
(jmccombs) - MLife

Locale: Southwest
Re: Re: Re: Lets rely on science on 05/22/2006 13:42:13 MDT Print View

Mr. Shannon. I think if I were a fan of % 15 would be a great number. The reason I'm not a fan of % is because as calories go from hypo to hyper there are certain macro nutrients that become more important. For instance if you are extremely hypocaloric research is clear that with adequate protein you can survive much longer than w/o. If you're interested search for protein sparing modified fastes.

Here's a paper (abstract) talking about GI. I think this is what you're after. If not let me know (like if you want to see something about high GI carbs pre-workout improving performance, etc.). Also if there's anything thats confusing let me know, I realize not everyone speaks the same dialect of nerd!

Diaz EO et. al. Glycaemic index effects on fuel partitioning in humans. Obes Rev. (2006) 7:219-26.

The purpose of this review was to examine the role of glycaemic index in fuel partitioning and body composition with emphasis on fat oxidation/storage in humans. This relationship is based on the hypothesis postulating that a higher serum glucose and insulin response induced by high-glycaemic carbohydrates promotes lower fat oxidation and higher fat storage in comparison with low-glycaemic carbohydrates. Thus, high-glycaemic index meals could contribute to the maintenance of excess weight in obese individuals and/or predispose obesity-prone subjects to weight gain. Several studies comparing the effects of meals with contrasting glycaemic carbohydrates for hours, days or weeks have failed to demonstrate any differential effect on fuel partitioning when either substrate oxidation or body composition measurements were performed. Apparently, the glycaemic index-induced serum insulin differences are not sufficient in magnitude and/or duration to modify fuel oxidation.

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Sustaining performance during a long mileage hike on 05/22/2006 17:58:05 MDT Print View

There's another aspect to this discussion that hasn't been mentioned, to my knowledge, and that seems to have a huge potential impact over time: glycogen repletion. From what I have been able to glean from the web and an exercise physiology textbook, glycogen repletion proceeds at a pace of about 5-7%/hr, which means that somewhere between 14-20 hours are required to replenish one's stores IF glycogen stores are completely exhausted. This much time is not practical on a hike such as Ryan's, I think. This could result in a steadily diminishing store of glycogen at the beginning of each succeeding day and eventually to gluconeogenisis. So it seems to me that the trick is hike at a pace, and for a period of time, each day that only depletes an amount of glycogen that can be repleted in the rest time available(10 hours?), and rely for the rest of one's calories on endogenous fat and carefully selected carried food. All coments gratefully received, and I am especially interested in hearing from those of you who, from past input, are obviously very knowledgable about exercise physiology. Many thanks in advance.

Jay McCombs
(jmccombs) - MLife

Locale: Southwest
Re: Sustaining performance during a long mileage hike on 05/22/2006 18:59:45 MDT Print View


I'm glad I found this thread. I mostly work with bodybuilders and haven't worked on endurance stuff in a long time (about 6 years). Things have changed a lot. I'm reading up on something called planned fat adaptation. Basically when you stop eating carbs there is a period of time where you feel like ass until your body switches to a more glucagon driven metabolism: basically a state of ketosis like those in atkins, south beach etc. They are safe given adequate calories and not too much time. Basically this theory says you can have athletes purposely deplete their glycogen in advance of their extended event so their body switches to using exclusively fat for fuel in advance. Might be a neat trick to use. I've just started collecting data and anecdotal reports from people on it but I'd love to hear if anyone here has any experience ideas. I think glycogen repletion is not a possibility for ryan because it sounds like from people's estimates before that he is going to be hypocaloric. I think we need to find a way to maximize performance under hypocaloric conditions. Ironically, bodybuilders do this all the time when they drop their body fat to insane levels to prepare for contests.

Edited by jmccombs on 05/22/2006 19:12:52 MDT.

Tom Kirchner
(ouzel) - MLife

Locale: Pacific Northwest/Sierra
Re: Re: Sustaining performance during a long mileage hike on 05/22/2006 20:00:58 MDT Print View

Hi Jay,
I wish I knew more about exercise physiology, but here goes with some feedback based on personal experience and what little I have picked up. In Ryan's case, he is going to be out for ~20 days which is a long time to burn fat only, since his performance level will drop due to fat not oxidizing as efficiently as glycogen. I would think he would then be faced with an even longer trip. I know that happened with me on a 17 day trip when I ran out of food and was basically living on trout the last 3 days. I was in ketosis big time(metallic taste in my mouth, lassitude, fuzzy thinking,etc). Also, the brain can't run on fat, if I understand things correctly, and so at least enough glucose/glycogen has to be replaced after the liver runs out to meet it's demands. Otherwise, gluconeogenisis sets in. At least some of what I have read claims that gluconeogenisis will also be triggered if the muscles run totally out of glycogen. But I guess that is what you are trying to avoid with the planned fat adaption program if I understand you correctly. I'd be very interested if it turns out to be a workable approach, because it would definitely extend a backpacker's range. I be very interested to know what you find out. I think Ryan pretty much knows he's going to go hypocaloric and is betting he can stave off the inevitable long enough to reach the "finish line". Let's all hope he doesn't end up a couple hundred miles short. I, for one, have gotten a lot out of this website and very much want him to continue as the driving force behind it. So just don't get too hypocaloric on us, Ryan! But look on the good side if you do: At least the bears and boogs will leave you alone.

cat morris
(catt) - F

Locale: Alaska
nuts! on 05/22/2006 20:17:05 MDT Print View

Brazil nuts & macadamia nuts pack a lot of calories & fat for their relative weight.

Jay McCombs
(jmccombs) - MLife

Locale: Southwest
Re: Re: Re: Sustaining performance during a long mileage hike on 05/22/2006 20:21:59 MDT Print View

Right, the first few days of ketosis can be VERY rought for some people. After about 5 days things start running like normal. You WILL run out of glycogen. Your brain and muscles can use ketone bodies, which it makes from fat, instead of glucose for fuel. It can also make glucose out of amino acids as I've mentioned.

I didn't realize he was planning 20 days. I was thinking like 7. So I'll have to talk to some friends and ponder on the idea a bit more. My initial idea would be:

1) get adapted to ketosis by eliminating carbs from the diet about 5 days before the hike.
2) do something called a "carb load" the day before the trip. You'll continue the fat adaptation for at least 7 days if you do this and have max glycogen stores to boot.

At this point I'll have to do some further thinking. Perhaps continue a diet of mostly fat and protein on the hike (<100g of carbs daily) to maintain fat adaptation and have weekly refeeds/carb loads where ryan has big calorie and carb days to help with performance. This way you only have to carry a couple high calorie days vs. more calories total for every day on a more traditional approach.

I'm not sure if that works physiologically as I'm sort of thinking out loud. Its an interesting thought at least. This would allow you to use body fat stores and dietary fat sources most efficiently and possibly allow you to maintain lean body mass on reduced calories for longer.

Havemann L, West SJ, Goedecke JH, Macdonald IA, St Clair Gibson A, Noakes TD, Lambert EV. Fat adaptation followed by carbohydrate loading compromises high-intensity sprint performance. J Appl Physiol. 2006 Jan;100(1):194-202.

Thats the paper I'm basing the theory off of right now. It basically showed athletes were impaired when trying to do a sprint on these types of diets but showed no detremental effects on a 100km cycle time trial (which would be more like what we would encounter hiking than a sprint). If anyone has any thoughts please let me know.

John S.
(jshann) - F
Re: Re: Re: Re: Sustaining performance during a long mileage hike on 05/22/2006 22:37:06 MDT Print View

I don't think Ryan should eliminate carbs before his hike at all. He should train properly, carbo load before his trip, and snack frequently during his hiking day to conserve his glycogen stores...just as Brenda Braaten states in her write up.

Casey Bowden
(clbowden) - MLife

Locale: Berkeley Hills
Re: Fat V Carb on 05/23/2006 11:32:16 MDT Print View

Al (or anyone else),

Regarding your "12 day un-resupplied 208 mile JMT hike" in which you "consumed 2 quarts of safflower oil from a platypus bladder".

I'm considering a 10 day un-resupplied south to north JMT hike this summer bringing only between 2500 to 3000 calories per day with the following assumptions:

1) Base pack weight including bear canister of approximately 10 pounds.

2) If I'm running short on food I will get snacks en route at the Muir Trail Ranch, VVR, Reds Meadow, Tuolumne, etc.

3) Losing 10 pounds during the trip would not cause me any grief (I'm in good shape but by no means an elite athlete).

4) I don't want to have to go to bed hungry!

Any input would be appreciated. Thanks in advance.

Bernard Shaw
( - F

Locale: Upstate New York
Re: Re: Fat V Carb on 05/23/2006 12:07:05 MDT Print View

I have been an elite athlete in my life and know a fair amount about this, including coaching distance athletes. Losing 10 lbs will not only reduce your energy levels during the trip, it can result in serious illnesses during and afterwards. Fasting is extremely dangerous, simply do not do it. When you have too little nutrients your body uses your muscles. Not good.

If you are concerned about saving weight follow the guidelines Braeton discusses regarding calorie dense and BALANCED foods. You can save allot of weight this way. Your body needs everything, fats, carbs, minerals, vitamins, etc. Don't skimp here. Eat ALL the time, I mean all day. Drink plenty of fluids AT THE SAME TIME YOU EAT to avoid hyponutremia too. (low electroyte condition).

Depending on your age, condition, pack weight and body weight, and total effort each day give yourself enough calories. Your ability to accomplish this will soar!

Most long distance folks, myself included have found the real secret to these events is to learn how to start out at the pace one will finish, to allow the body 3 days to acclimatize both to the effort and altitude, and to be steady with mini breaks for stretching, yoga, and micro naps.

Good luck!

Edited by on 05/23/2006 12:08:57 MDT.

Casey Bowden
(clbowden) - MLife

Locale: Berkeley Hills
Re: Fat V Carb on 05/23/2006 12:41:23 MDT Print View

Evan (or Bernard?),

Thanks for your input. Please note that I don't intend to "fast" during the hike. I'm just trying to find an optimal amount of food to bring. I should have added the following to my initial post.

Last summer my wife and I did the Rae Lakes Loop. We planned and brought food for a 5-day trip but ended up finishing in only 2.5 days including a side trip to Sixty Lakes Basin. Despite our fast pace we still didn't eat all of the food we budgeted (2600 calories per day per person) for each day nor were we hungry!

I am specifically worried that on day 4 or 5 of my JMT trip my metabolism will kick in and I'll be hungry. However, by that point I'll be able to buy extra supplies at the Muir Trail Ranch, Reds, etc. so maybe it makes since to not bring to much food.

Jay McCombs
(jmccombs) - MLife

Locale: Southwest
Re: Re: Re: Re: Re: Sustaining performance during a long mileage hike on 05/23/2006 20:59:02 MDT Print View


Maybe I didn't do a good job of explaining my rationale. So let me try again.

1) I'm assuming that due to unavoidable circumstances Ryan is going to end up at a net negative energy balance in that he is going to be using more calories than he can eat. This will make maintaining glycogen stores pretty difficult, if not impossible, and throw conventional wisdom about athletes and nutrition out the window as this is all based on the idea that athletes are hypercaloric or at least isocaloric.

2) Eventually he's going to start catabolizing body energy stores. After glycogen you have two other storage depots: adipose tissue and muscle. The key is something called "partitioning" where in you do all you can to keep the calories coming from adipose tissue instead of muscle.
3) The glucose dependent organs (muscle, brain, etc) can substitute ketone bodies made by the liver from fat for glucose. As anyone that has tried one of the low carb fad diets will tell you the first couple days are very difficult but eventually your body adapts and you feel "normal" I would have Ryan undergo this adaptation phase when there isn't anything at stake, ie, before the hike.
4) At some point Ryan, or any hiker in his condition, will have to start catabolizing tissue for fuel. If you reduce carbs in advance and pre-condition your body to start running off ketone bodies you can spare yourself the week of adjustment time and be adapted to use dietary and body fat preferntially and avoid catabolizing muscle (assuming adequate intake of protein which I feel safe setting at 1g/lb).

5) Ideally I would want ryan or anyone to simply eat enough calories and follow a traditional dieting approach. I don't think thats an option. Research I found on people doing antartic crossing pulling sleds for 90 days showed them to be fairly malnourished eating 4000 calories a day. The key goals need to be maintaining high levels of protein synthesis. Insuring efficient usage of body and dietary energy sources. Those boht meet the ultimate goal of not starving or at least starving with grace.

Its just something I proposed that I thought might work in this sittuation. Maybe others will try it on shorter duration trips in less remote places. Or maybe it will be written off as hersey :)

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Sustaining performance during a long mileage hike on 05/26/2006 14:04:15 MDT Print View

What about packing on a few (and i do mean a few) extra pounds before the trip? I find that all too easy to do on a daily basis :)

kevin davidson
(kdesign) - F

Locale: Mythical State of Jefferson
Storing up some xtra #'s on 05/26/2006 14:58:33 MDT Print View

Ice cream is good for this. Say a pint of Haagen-Daz a day for a week prior to your journey. I hear that Ryan Jordan might be chewing whale blubber shortly before he starts the Arctic 1000 death-jog. :-)>

Edited by kdesign on 05/26/2006 15:00:25 MDT.

Al Shaver
(Al_T.Tude) - F - M

Locale: High Sierra and CA Central Coast
re. Fat V Carb on 05/29/2006 00:30:31 MDT Print View

On 2500-3000 Cal/day plus mid-trip binges, ultra light pack and covering only 21 mile/day average, I would think it would be nigh impossible for you to lose a pound of body weight/day as you suggest (unless you are extremely large or have the basal metabolism of a hummingbird on amphetamines).

The high oil diet worked for me (although there were palatability issues after a few days). But I can only advise others to try it first for a few days before committing to it for extended periods.

If you take many days to slowly ascend to altitude and then spend 3 weeks above 10k' adjusting to it (as I will this summer), you will maximize your performance. If you're not willing to invest this amount of time, the slower you ascend and the more days you spend doing it, the better you will feel and perform when you start at the JMT's 14,500' southern terminus.

If you only take 3 days to pre-acclimate, you can save weight by carrying small meals for the first 3 days on the trail. Anorexia is a very common symptom of Acute Mountain Sickness (AMS) and you will likely not have much appetite despite your physical exertion. The flipside of this is that around day 4 your appetite will likely kick in like gang busters. Fortunately, at your pace you should be close to your first binge station by then.

" steady with mini breaks for stretching, yoga, and micro naps." I like this advice from Bernard. JMT speed record holder Kevin Sawchuk is a proponent of micro naps. My only concern is that a micro could turn into a macro as I awake 14 hours later being gently nudged by a bear's nose rummaging for food inside the body of the pack that I'm still wearing!

Good-Luck, Casey. Please post the results of your trip in the "Trip Reports" forum.

Cheers, Al

Edited by Al_T.Tude on 05/29/2006 01:04:25 MDT.

Casey Bowden
(clbowden) - MLife

Locale: Berkeley Hills
Fruit/Nut Ratio on 05/31/2006 09:43:53 MDT Print View


Thanks for the input. I have been wondering for some time how long it takes for ones appetite to catch up with ones expenditure as on my short length but high mileage trips it never has.

Have you posted details of your trip in the "Trip Reports" forum? I would be very interested in the details.

I would also be interested in your take on Coup's JMT through hike. It is very useful for the backpacking community when someone experiments and then posts the results for all to see. Coup says he only ate 1.6 pounds of fruit and nuts per day although the caloric intake could vary quite a bit depending on the fruit/nut ratio. My wife thinks that my fruit/nut ratio is pretty high!

Re: Fruit/Nut Ratio on 05/31/2006 13:51:11 MDT Print View

What do you all think the Fruit/Nut Ratio in these forums is? :-)