Ketogenic diet as a way to lighten pack?

From wikipedia

"The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children.

The ketogenic diet is not a benign, holistic or natural treatment for epilepsy.

In adults, common side effects include weight loss, constipation, raised cholesterol levels and, in women, menstrual irregularities including amenorrhoea."

Sounds pretty serious to me.

Piper, your diet is not that unusual. In the low carb literature, such as researched by Dr. Michael Eades, M.D. (author of the Protein Power diet), and others, the Eskimos lived on this diet for centuries (a totally carb-free diet).

I have long thought of backpacking as really being spine/muscle-out weight is what you're packing and if one could get their body fat % down to ideal levels, the hike would be that much more fun, one would be more energetic, and the weight you're carrying would truly feel that more lighter. (Instead of focusing on skin-out weight only.)

I tried unsuccessfully to achieve that ideal body fat percentage via dieting and exercise combined (I typically eat (while not on the trail) a Paleolithic diet that is Zone balanced (40% calories are carbs from fruit/vegetables; 30% calories from protein; 30% from healthy fat).

However, recently (a little over 6 weeks ago), I discovered two books that according to all the research will add decades of health to one's life. The one is free in ebook form: The Fast-5 Diet ( http://www.fast-5.com ) and the other is a $39 book, the Eat-Stop-Eat Diet from http://www.eatstopeat.com .

Quite simply these two books supplement your existing diet, not replace them. The idea is to give your body intermittent fasting periods through the week and they explain what happens biologically during intermittent fasts (such as one releases 20 times as much human growth hormone during an intermittent fast than during a normal eating day). Page 61 of Eat-Stop-Eat:

"A very impressive volume of published peer reviewed scientific studies, short-term
intermittent fasting has been shown to have the following health benefits:

• Decreased body fat & body weight
• Maintenance of skeletal muscle mass
• Decreased blood glucose levels
• Decreased insulin levels & increased insulin sensitivity
• Increased lipolysis & fat oxidation
• Increased Uncoupling Protein 3 mRNA
• Increased norepinephrine & epinephrine levels
• Increased Glucagon levels
• Increased growth hormone levels
• Decreased food related stress
• Decreased chronic systemic Inflammation

Quite a list I’m sure you will agree. What is even more amazing is that many of the
benefits were found after as little as 24 hours of fasting!

From experience in the supplement industry, I can tell you that if you could make a
pill with all these claims, you would easily have a 100 million dollar a year product."

The other book, Fast-5, written by a M.D. explains there are two hunger mechanisms — one triggered by a long fast (in me, I've noticed it is about 31 hours) while the other hunger mechanism is triggered by having one bite of food (which is why reduced calorie diets fail typically, because one's will power is not enough to overcome this hunger mechanism in 99% of people) — the research on intermittent fasting shows that mice who continuously eat the same number of calories that the intermittent fasting mice eat (except they go without any food 1 out of 3 days), that is assume the mice eat 6000 calories in six days in both groups, in one group the mice eat 1000 calories a day, the other group the mice eat 1500 calories a day two days straight then fast the third day. The intermittent fasting mice live 33% longer than the other group of mice, and the intermittent fasting mice lose more weight! The other group of mice suffer more stress (because they're continually having a reduced calorie diet). (I've simplified the numbers here to illustrate the finding.)

I've only been on the diet since October 9 and I've lost 15.5 pounds already. I'm down to 175.5 pounds and wear medium size pants now — first time since about 1994. My goal is to continue until I get to 14% body fat (a man's goal is < 15%, a woman's goal is < 22%). My scale from Tanita (from Sears) tells me my body fat percentage. But in maintenance mode I still want to fast at least once a week a whole day and in the interim days do a couple of Fast-5 short intermittent fasts. (On the Fast-5 diet, you only eat during 5pm to 10pm daily and in maintenance mode, you do this a couple days a week. On the Eat-Stop-Eat diet, you minimally do every 3rd then 4th day a 24 hour fasting period, say from 6pm to 6pm, although with me I've gone the excess route of a whole waking day fast which ends up being about 31 hours long with the two sleeping periods surrounding the fast.)

Wikipedia has some interesting pages of links on this — "intermittent fasting" and "caloric reduction". One can also google "Alternate Day Fasting".

Edited: 11/27/2011 — corrected percentages on the Zone Diet (had two reversed originally).

In theory, both of those intermittent fasting methods, when added to a Paleo-style diet, should more accurately reproduce the caloric intake of our ancestors, in frequency and quality. I'm not in a position to do nutritional research, but I always imagined a Paleolithic hunter-gatherer society having periods of gorging and periods of fasting, dependent on when the hunters were successful. Most of the reactions to intermittent fasting that those books list make perfect sense as metabolic responses to a short term food deficit brought on by a tribe waiting for the hunt to come home.

The research there looks quite interesting and I will definately read through it but one thing that often gets confused is that just because it was the way early man evolved doesn't mean it is the opitmim way.

We must remember that evolution only weeds out unsuccessful adaptations. Essentially weeding out those who are not able to successfully reproduce. So in early man the key was to survive and breed as often as possible between 14 and 40 when you died and ensure that the children you had made it to breeding age. This doesn't neccessarily translate into living well as you age.

So while I am a big proponent of clean unprocessed foods I do think that replicating early diets definately needs to be backed with research and is too often accepted without research under the logic of it was what our ancestors did.

If a diet works for you great! On the other hand I'm also skeptical that just because our ancestors ate something that automatically means its the ultimate diet. First off we don't have a detailed knowledge of what folks were eating thousands of years ago and what proportions of that they ate. We can guess based on what foods we know would have been available but thats not very precise.
Is it just me or are diets a dime a dozen? I guess there are different reasons for diets, losing weight, gaining muscle, dealing with cholesteral or whatever. But still there seems to be no concensus out there. This lack of consensus makes me skeptical when people start promoting a new idea of whats healthy for me.

"If a diet works for you great! On the other hand I'm also skeptical that just because our ancestors ate something that automatically means its the ultimate diet. First off we don't have a detailed knowledge of what folks were eating thousands of years ago and what proportions of that they ate. We can guess based on what foods we know would have been available but thats not very precise.
Is it just me or are diets a dime a dozen? I guess there are different reasons for diets, losing weight, gaining muscle, dealing with cholesteral or whatever. But still there seems to be no concensus out there. This lack of consensus makes me skeptical when people start promoting a new idea of whats healthy for me."

+1

Any diet that doesn't include enough carbs to enable the metabolism of fat will just force the body to utilize a less efficient process of breaking down protein, either dietary or muscle, to obtain the necessary carbohydrate. A byproduct of this process is urea which must be eliminated via the kidneys, requiring increased water intake. Why not just eat a balanced diet of carbs, fats, and proteins in a quantity calibrated to your activity level and let it go at that? My 2 cents.

I'm not sure I wanted to debate whether or not a low carb, high fat diet was a good one. However, it is nice to see that there are people here who understand how it works. I am not doing the Paleo diet because I still eat some cheese, cream and butter. I've been following the information from Dr. Eades and Dr. Harris.

What I was curious about is once you have accomplished switching your body over to a state where your body can mobilize your fat stores for energy, in other words, once you've keto-adapted, would a dinner that did not raise your insulin leave you better able to manage a long, cold night sleeping on the snow? Better than a dinner that did raise your insulin?

sounds like an Atkin-nese diet

I have had several acquaintances that have been on similar diets, all lost a significant amount of weight- sadly all have gained it back :(

I'm on the "pretty much eat what you want diet" and have been since I was a kid, it appears that if your caloric burning level is on the higher end, then diet becomes much less of an issue

I do and try to eat healthy (whole grains, fruits, veggies, lower fat meats (read elk/deer/antelope)) overall and I'm not too much a glutton (excluding yesterday! :)), but I spend more time concerned about exercise and much less about diet

As a Type 1 diabetic I've had to directly deal with learning how to visibly control my blood sugars so that I can get some control over the disease. Nothing worked until I started to learn about how insulin works and how carbohydrates affects it. The thing that most people don't understand is that diabetes is a reflection of the problems of the way we eat in our society. Diabetes and obesity (which are related through insulin) hardly existed in any society before the advent of modern food processing methods, and a little earlier, the development of grain-based agriculture. All paleoanthropological evidence shows that modern diseases such as diabetes, arthritis, cancer, obesity, coeliac disease and so forth, were extremely rare in paleolithic times. This strongly suggests… and more and more research is showing it so… that there is something wrong with the way we eat today. The current obesity problem in the States is unprecedented in history. Due to the foods we eat, it simply isn't possible that fat (the popularly maligned nutrient) is the culprit, since with each meal only a certain amount of fat can be eaten before one becomes satiated. What has increased exponentially are carbohydrates. Until you actually take heed, in the same way that you weigh each item in a UL gear list, of the amount of carbohydrates that you consume each day in each bit of food you eat, most people have no idea just how much of it there is. Go into any store and look for anything that doesn't have any carbohydrates… today almost nothing is free of them. For health the minimum amount of carbohydrates that you need is about 30 to 40 g of carbohydrates a day, the upper limit is about 150 g, after which the higher you go the more you automatically start gaining weight. In nature most carbs come from the vegetables you eat, which are a vital part of one's diet. Grains, however, have never been a part of the human anatomical development. Even cows can't digest grains!

As a diabetic I check my blood sugar four times a day. I've been doing it for 15 years. Unlike most people I have visual and measured confirmation of how the food I eat affects my blood sugar. Without going into the intricacies of how insulin works with carbohydrates, suffice it to say that no matter how much fat I eat (without accompanying carbs) my blood sugars don't go up. If I eat just a tiny amount of carbs, though, especially things like white sugar and white bread, my blood sugar shoots up. For most of the last 15 years I religiously followed the conventional guidelines of eating low-fat, high-carb diet, mostly vegetarian, and not only did I become diabetic, but I gained weight and had little control of my blood sugars, which is the heart of what causes diabetes. Last June, after reading "The Diabetic Solution" by Dr. Richard Bernstein, and "Primal Blueprint" by Mark Sisson, I tried lowering my carbs for the first time in my life, and upping the fats. To my utter surprise, my blood sugars completely normalized and all my diabetic symptoms went away. including neuropathy of the extremities, a three-year-long fungal infection of my right hand, and even the tinitus in my ears. My HbA1C (long-term blood sugar measurement which is more accurate than home measurements) lowered for the first time in 15 years. My doctor was incredulous. My energy levels went way up, colds disappeared, and I felt better than I had in over 25 years.

Recently I started reading Philip Maffetone's "The Big Book of Endurance Training". Whereas "The Primal Blueprint" goes into great detail about the effects of nutrition, and especially does the best job of explaining insulin and how it works and causes problems, Maffetone's book concentrates on the physical training aspect of "aerobic" and "anaerobic" training. Maffetone explains that aerobic exercise is primarily fat-burning based, whereas anaerobic exercise is glucose-based. Endurance athletes (and this includes mountain walkers) need the slow burn of the fat-burning metabolism, while athletes such as weight lifters and sprinters need the quick energy of sugar-based metabolism. Through decades and thousands of meticulously tested and recorded training of world-class elite athletes, Maffetone came to the conclusion that the healthiest people maintained the best health by focusing on an aerobic threshold, including those people who needed anaerobic development to do their activities. He emphasized that the moment the aerobic base is compromised, all the rest gets compromised as well.

What surprised me was that I had always been taught that aerobic exercise had something to do with the amount of oxygen in the blood and that the more you did, and the harder your trained, the better. Maffetone, however, explains that pushing yourself beyond the threshold of your aerobic base, which falls within the energy output of a fat-based metabolism, is the primary cause of injury, disease, and poor performance. He advocates a low carbohydrate, high fat, moderate protein diet, plus a low level of exercise that never pushes beyond the capability of the aerobic system's threshold. For that a person needs at least three months of slow, easy training (using a a heart rate monitor and maintaining the heart rate within specific levels) so as to train the body to using primarily fat for energy… the ketogenic diet. Most people, because they eat diets high in carbs and push themselves beyond the aerobic level, tend to need more and more carbs in order to maintain their energy levels, with the resulting problems with weight gain, bad blood sugar control and over-production of insulin (which leads to obesity and eventually diabetes), and overtraining. Most people have glucose-based metabolisms. That is why it took Piper 6 weeks to change over to a fat-burning metabolism.

If Maffetone's elite endurance athletes (including many of the world's best ultramarathoners and triathletes) can perform so exceptionally well on a this system without injuries or stress, while often coming from careers ruined by overtraining and carb-bsed diets, then there must be something to the low-carb, high-fat, moderate protein and lots of vegetables recommendations coming out now in paleo circles. Logically it doesn't make sense that there isn't an ideal diet for humans, whereas we seem to have no trouble at all coming up with ideal diets for our pets. We're animals, too, and also have specific needs in nutrition.

That being said, humans are omnivores and adaptable, including with our food. Other books you might want to check out are, "The Omnivore's Dilemma: A Natural History of Four Meals" by Michael Pollan, "Good Calories, Bad Calories" by Gary Taubes, "Deep Nutrition: Why Your Genes Need Traditional Food" by Catherine Shanahan, and "Slow Burn: Burn Fat Faster By Exercising Slower" by Stu Mittleman.

I think people should try out the diet and learn more about how nutrition works before pooh-poohing what it can do. I was very skeptical before I started, especially since, with diabetes, I can't afford to play around with my metabolism. Among diabetics low carb is becoming the de-facto way of maintaining blood sugar control… and a healthy diabetic lifestyle is a healthy lifestyle for anyone.

Piper, I think you really have something there about maintaining heat at night. It could even be said that perhaps many women are colder in the mountains because they tend to eat far less fat than men, and therefore end up with colder metabolisms. It's worth looking more into.

I understand lots of people gain weight back after a diet so that may not be a problem with the diet.
I'm still relatively young and apparently have a high matabolism so I don't have to worry about my weight especially since my noraml diet is relatively healthy. Long term I'd be more interested in what diet is best for preventing long term problems like heart disease but honestly I'm skeptical just how much is proven fact in this area beyond common sense like "eat a balanced diet not a lot of junk food."
I have had friends passionately telling me the problem in America is too much protein/meat products while diets like the Atkins seem to include lots of it. Of course there is money to be made writing health guides and selling products so that introduces a bias. I'm sure there is a best way I just need to sit down and works for them. When I say I'm a skeptic I'm just being realistic. I'm not going to take a diet off a magizine in the supermarket checkout line and run with it. If I change my diet I'm going to need to seriously study the issue.

I still think lifestyle is as important as diet. Obviously our modern lifestyle creates problems. Not only are we more sedatary on average but a fast paced life means getting a healthy meal is difficult. Its not impossible of course, you just have to make an effort. Its easy to just grab a cheeseburger.

When I worked with troubled boys at a wilderness camp we had a very nice menu of food that wasn't more or less the food pyramid. Normally counselors would serve the boys their food so they got a balanced serving of everything. Along with that we stayed active. A lot of counselors and campers lost weight just by limiting themselves to one balanced plate and perhaps skipping desert. Some of our campers had the opposite problem. Apparently their behavioral meds kept their appatite down which was probably aggrevated by a choatic home life without regular meals. They would come in looking like little war refugees. One very skinny boy gained gained 8 pounds in about a month. By the time he left us he had the most muscular build I've ever seen on an 11 year old.

Luke, I definitely recommend you read Philip Maffetone's "The Big Book of Endurance Training". He'll explain far better than I can how it all works. Big muscles are not, he insists, an indication of good health. In fact he also insists that concentrating on putting on big muscles is detrimental to most people's health. Besides, your scenario most definitely is not a long-term healthy one.

The paleo diet is not the Atkins diet. Vegetables are very much a huge part of the paleo diet. Personally I follow Mark Sisson's "primal" recommendations, in that he includes a higher amount of carbs because of the vital benefits of vegetables.

I didn't know what paleo (or primal) was about until I seriously started reading about it and practicing it. I think people get too skeptical of things that they haven't actually learned about or tried themselves. The thing I respect and can accept about paleo is that nearly all of it is based heavily on real research and much skepticism, and trial and error. Mark Sisson himself, on his very popular website "Mark's Daily Apple", frequently hosts skeptics, often scientists and nutritionists, who take him to task. Over the years he's revised what he's learned and is always willing to learn more. The whole paleo movement is very healthy and open-minded. The whole community very much reminds me of the early BPL days, with the same commitment to honesty and enthusiastic testing, with health, not weight, the focus.

My reply is to give you a intro link about three key people in the Paleolithic Diet movement. All three have made very significant contributions. I have more links at my Google Profile (see my BPL profile).

http://jdmoyer.com/2010/03/17/a-meta-analysis-of-kooky-diets-part-iii/

This is a photo of At Devany, author of The New Evolution Diet, who is now age 72. I hope I can be this healthy at his age. He's doing something right. He mixes the Paleolithic Diet with Intermittent Fasting and Weight Resistance workouts.

Best page of links about Paleolithic diet is here: http://paleodiet.com/

Best intro to the diet is considered this page by a M.D.:
http://paleolithicdiet.wordpress.com/2008/06/22/original-introduction/

I used to weight 200 lbs … I lost it without any real diet … The old fashion way …. Exercize

Thats not to say you shouldnt eat healthy with more natural foods … But exercise trumps fancy diets any day

The trick to remember with all these paleo diets is that our ancestors also exercized alot … Running away from sabertooths and hunting mastadons is a great incentive to stay in shape

Exercise is hard, and its sweaty, and you likely wont see any gains for months (i didnt) … But if you truly want to get fit its the only way

Its been shown to also decrease the loss of cognitive function with age and give better sex drive ;)

My view … Skip the diet … Spend more time at the pool, park, track, etc … And commit to exercising as hard as reasonably possible

Millions of americans are taken in by the diet craze every year … And millions are still overweight …

After u exercise to a healthy enough level you can eat what you want … Im typing this on my phone while drinking a 800 calories sbucks frap …. But then im swimming 2 klicks tonight …

Miguel very interesting stuff (your first post came out while I was typing mine). If I have time I might be checking out those books, looks like a good place to start.

Couple thoughts…
Regarding grains, hasn't grain and bread been a part of the human diet for about 5000 years or so? I'm assuming the first record of it would be the agriculture in the Mesopotamian area. Are you implying that bread is a contributing factor? Whats the difference between whole wheat and the modern white bread? After reading up on diet my mom desided never to buy the family white bread again but we ate plenty of whole wheat bread (mostly homemade). How do the two breads compare on the number of carbs?

You said my scenerio wasn't healthy in the long term. I assume you meant the young man who bulked up not the guys who lost weight. I'd tend to disagree but maybe I wasn't clear. He didn't have huge movie star muscles, but what he had was well defined and he was very strong for his age. He did put on weight fast for a while but than it stopped and he started growing and gaining weight more like an average kid. He wasn't liftind weights or anything like that he was just living an active lifestyle which involved a lot of physical activity but nothing extremely rigorious (i.e. the kind where a growing kid could get hurt).

Whats the traditional Japanese diet like? I believe someone told me the Japanese have a lower rate of heart disease and other problems and were overal a bit healthier. Is that diet based? On the other hand could some of that simply be genetic since we're talking about a distinct ethnic group thats been relatively stable for a long time? Also I heard the average height in Japan increased when they moved to a more western diet. Could this be just greater prosperity in general or could it be because for all the bad things in the western diet there was something missing from the Japanese diet?

Check out "Intermittent Fasting" at Wikipedia or Google. You'll see that mice given the same calories, one set on continuous avaibility to eat, other deprived of food every third day, that the mice who do the intermittent fasting live 33% to 50% longer.

Exercise alone won't do this for the mice; diet alone won't do this for the mice.

Also there is plenty of evidence that reducing calories but eating 3 meals a day is for many many people stressful as one has to use will power to keep their caloric intake in check. With Intermittent Fasting, when you eat, will power is not needed, it's stress free. (Hardly any will power is needed to fast because you don't trigger the strong hunger mechanism that having one bite of food triggers — read the book, Fast-5 Diet, which is free at http://www.fast-5.com .

Science has known about prolonged living with Intermittent Fasting since the 50s. The same scientist who chemically stopped aging in Tape (Scotch Magic Tape) spent 25 years researching aging in humans and he discovered and wrote abundantly about this. I would have done intermittent fasting earlier if I had not been deluded by all the wife tales and myths surrounding Intermittent Fasting. The book, Eat-Stop-Eat, blows all of these myths apart.

It's interesting that on that a group of humans in an Intermittent Fasting experiment, that they released 20 times more Human Growth Hormone on their fasting day than on their eating day. That is definitely healthy for one (and that HGH helps really burn fat too).

http://blogs.menshealth.com/health-headlines/fast-to-burn-fat-not-so-fast/2011/04/18

This is all really interesting information.

"Big muscles are not, he insists, an indication of good health. In fact he also insists that concentrating on putting on big muscles is detrimental to most people's health. "

I would not agree with this based soley on the fact that to get a larger cross section of muscle fibres (i.e. size) one needs to increase strength. Strength training is vital for people as they age. Strength training maintains muscle mass and prevents joint strain.

Studies also show that strength training vastly increases the muscles ability to endure constant tension and hence, over all endurance. Specific endurance training will not improve strength to a measurable degree but strength training will increase endurance measurably.

I am going to read more on this diet. Some facinating results to be sure.

I would not agree with this based soley on the fact that to get a larger cross section of muscle fibres (i.e. size) one needs to increase strength. Strength training is vital for people as they age. Strength training maintains muscle mass and prevents joint strain.

David, Maffetone specifically does suggest that for people over 45 doing weight training and strengthening the muscles is vital for maintaining health. But the book goes into great detail to show how anaerobic training should only be performed after a healthy aerobic base has been established, and that if the aerobic base is compromised all anaerobic training should be stopped until the aerobic base is healed. He doesn't say strength-training shouldn't be performed (after all he trained Olympic athletes and all manner of world-class level elite athletes around the world), but that long-term health and what all people need before anything else, is an well-balanced aerobic base. He also explains how it is the aerobic muscles (the long, thin "red" muscles) that hold the skeleton and joints together and hold up the body, not the anaerobic (big, white) muscles, whose only purpose is short bursts of power. He even shows how anaerobic muscles, because they rely on glucose to power them, and because the glucose-based metabolism only holds about 3 minutes worth of energy, cannot be the base for moving the body about and getting on with long-term day-to-day activities.

Think about it; it really makes sense. Why did we develop the ability to store fat on our bodies? What purpose does that serve? People talk about body fat as only an inconvenience and detriment to health, but if it didn't serve a purpose toward our survival it would not have developed. Why did our bodies evolve to store fat instead of glucose? Fat has far more energy storing capacity than either carbs or proteins (fat: 9 kcal/gram vs. carb/protein: 4 kcal/gram). It releases slowly over time. Energy from fat is the brain's preferred source of energy (the brain is mostly made of fat). And fat is vital to the proper functioning of all our cells.

By developing a fat-based metabolism the body then has an enormous source of energy to draw from. It helps us get through times of famine, such as long winters. Most animals, and humans among them, donn't move about a fast speeds all the time… most of the time they move slowly and deliberately. Fat burning is ideal for that… sugar burning goes by too fast and glucose stores in the muscles (white muscles) quickly gets depleted. People in the past walked huge distances around the globe (not ran) and relied very much on their fat stores to make those distances. They couldn't have done it on a carb-based diet unless they had a steady supply of carbs to take with them. In the wild, carbs are very hard to come by, especially during the ice ages.

Big muscles and sugar based sources of power are great for short bursts of strength such as climbing a tree or sprinting from danger, and are still necessary for overall health, but they are not necessary. Strong red muscles are, though, so that the skeletal system and joints, as you, David, point out, can hold up through old age.

Luke, I'm not ignoring your questions… just ran out of time to write. Give me a day or two. I'm heading out to the mountains now…

All right Miguel I'll look forward to hearing further thoughts from you after you get back from the mountains. Enjoy them for me.

"He even shows how anaerobic muscles, because they rely on glucose to power them, and because the glucose-based metabolism only holds about 3 minutes worth of energy, cannot be the base for moving the body about and getting on with long-term day-to-day activities."

I haven't read Maffetone's book, Miguel, but I have read a fair amount of exercise physiology, and this statement runs counter to everything I have read. Glucose requires external oxygen for complete oxidation. It carries 6 of the 12 oxygen atoms required for its complete oxidation in its molecular structure, but the other 6 must be supplied via the cardio vascular system, i.e., aerobically. Those 3 minutes of anaerobic energy are supplied first by ATP stores, good for 10-20 seconds, and second by the creatine cycle, good for about 2 minutes. Any exercise after that must be aerobic. The body stores up to ~400-450 grams of glucose as glycogen, in the liver and muscles, enough to run about the first 20 miles of a marathon, where most runners "hit the wall". But glucose is not the only source of energy utilized. As you state, fat also supplies energy. In fact it supplies most of our energy at lower levels of exertion, and higher levels of fat utilization can be attained by pushing your aerobic threshold higher through training, again as you have stated. This is what keeps elite marathoners from hitting the wall. However, a certain amount of carbohydrate is required to facilitate the metabolism of fat in a process known as The Krebs Cycle. I think this is pretty well accepted by physiologists, exercise and otherwise. The proportion of energy supplied by fat and carbohydrate varies according to the intensity of the exercise and the aerobic capacity of the individual. The lower the intensity, the higher proportion of energy supplied by fat, and vice versa. At least, this is what my reading tells me.

As for the brain's energy source, I would refer you to the following link, one among many that say the same thing: The primary energy source for the brain is glucose.

http://www.acnp.org/g4/gn401000064/ch064.html

Just a few comments.

-not everyone has the same number of red and white fibers.

-red fibres have very little propensity for maximum contraction and therefore strength.

-strength and power are not the same thing and must be for differently.

-white fibres are used for shorter bursts of energy but that is a maximum effort. Having very strong white fibres increases endurance in a way that can be analogous to a large motor v.s. a small motor in the same sized car. A larger motor does not have to work nearly as hard as the smaller motor at low to moderate intensities. Just because you have increased the ability to maximally contract the white fibres by increasing strength, it does not mean that you will be contracting them at maximal intensity all the time. Think reserves.

-only the strong survive (just kidding)

"-only the strong survive"

Sure, but only the good die young.

I'm gonna live to be very, very old……

Tom, how do these experts who state that the primary energy source for the brain is glucose or that a certain amount of carbohydrate is required to facilitate the metabolism of fat account for the fact that Eskimos have lived centuries on a totally carb-free diet? I'm sure they use plenty of brain power to survive in such a hostile environment.

Can you imagine our hunter-gatherer ancestors starting out a day when they intend to hunt by saying "I have to carb up to do the hunt today" — yea, with what? How could they have ever carb'd up or carb'd out? Their diet lacked anything that was carb dense. This was the case for tens of thousands of years. We'd have gone extinct if such was true about carbohydrates as many cited experts claim.

I can imagine the retort would be that including carbohydrates in the diet enable the society to be more advanced. Maybe, maybe not. It's pretty rare to see carb-free societies, and in the Artic, that's pretty much where such could be the case. For myself, I believe in having about 30% of my calories come from low glycemic carbs (fruits and vegetables though).

My understanding but I'm not anywhere a professional in these fields, is that body fat consumed can be utilized as carbohydrate energy (same for fat in food too). That would explain how our ancestors and the Eskimos are (were) able to think.

The one thing you learn fast in researching nutrition is how little consensus there is across the various dietary research endeavors except for most of them do prefer natural food over artificial food but even then their are those who defend GMO food (and some of these work for the FDA).

In the end, one has to go with what works for one's self, backed up with some degree of research you're not going totally off the deep end (just about anything works for a short while for one's self).

I'm rushing out the door, so can't take a lot of time to write, but I wanted to say, to everyone, I am in no way an expert on any of this. I'm still at the beginning of learning the basics! So Tom, David… I'm completely open to learning more about all this and how it works. I've read quite a lot in the last three years, particularly this year, but only now is much of it making any sense or one part beginning to click with another. I still don't really understand how the energy from fat works with the brain, compared with the energy from carbs, but in my personal experience with high and low diabetic blood sugars, there is a visceral difference in both my feelings of alertness and wellness, and of perceived mental and emotional acuity when eating different kinds of foods… I'd say it is much like the difference in drinking strong coffee (with its caffeine) and drinking, say, orange juice. I can physically feel the difference between high blood sugar and low blood sugar, and my energy levels are different. This is different from how many calories I've consumed. I can eat a big plate of 4 slices of bacon, 3 buttered, scrambled eggs, and round of avocado… a meal which has a lot of calories, but my blood sugar will remain low (and my insulin injection will be very low so as to keep myself from dropping into hypoglycemia), while a meal of a simple tuna sandwich with white bread… with much lower calories than the former meal… will shoot my blood sugar way up, require a big dose of insulin and will only give me energy for about two hours, while the high-fat diet will often keep me going all day long. I don't gain weight on the high fat meal, but I do gain weight with the smaller, high carb diet, in spite of there being less calories. I still don't understand how this works chemically and biologically. But it does. The same way Piper has found out. I tend to eat far less with a high-fat diet. I never get hungry. And my blood sugar spikes have disappeared.

That being said, after some trauma in August when I was hospitalized, I started eating carbs again, mostly bread, but not in any high amounts. I've gained back all my weight, my blood sugars are sky high again, the fungus is slowly returning on my fingers, and I'm tired all the time again. I'm almost certain now that carbs are the culprit for most people.

Luke,

Unfortunately you aren't going to run into much "proven fact", and to make things worse, much of what sounds like common sense is probably incorrect. Our current knowledge of how the body works is continually being added to, and so what appears initially correct may be turned on its head as additional details come to light. This can seem a bit futile, but the overall trend is positive. (Consider things like the germ theory of disease, antibiotics, and monoclonal antibodies.) Unfortunately it also gives us things like margarine and low-fat diets.

Since I grabbed dinner before finishing this reply, I saw you had some other questions:

1. Correct, grains date back much farther than 5k years; closer to 10K is more likely for domestication in the mideast. (Wiki claims some use of wild barley 23K years ago.) Evolutionarily speaking, this is still quite recent.

1a. Yes, modern grain is quite different from that a century ago, or a millenia ago. Most wheat is now a dwarf wheat, which helps increase yield. The gluten content is also higher than in the past.

1b. Whole wheat includes the bran and germ; so you have more protein, fiber, and some additional nutrients. It also seems to confer health benefits compared to refined flour. (Or from an alternate viewpoint, may be less harmful.) However, there are different types of wheat with different gluten amounts, and you can even find "archaic" wheat like einkorn if you look around.

2. Looking at cultures (e.g. Japanese) means that many factors are in play: genetics, diet, behavior, climate, etc. It's a big can of worms. The best I can say is that there seem to be certain "diseases of civilization" that are minimally present in aboriginal societies, even when accounting for decreased average lifespan. If pressed to identify dietary factors with the strongest correlation, I would point to wheat and refined sugar.