08 February 2009

All Medical Science is Wrong within a 95 % Confidence Interval
or: A Review of Taubes' "Good Calories, Bad Calories"

Recently I read a very impressive book by Gary Taubes, previously a reporter for the journal Science. The work in question is, "Good Calories, Bad Calories."' In the book, Taubes collects research to challenge the common knowledge of nutrition: that fat is bad for you, that we should eat polyunsaturated vegetable oils, that we should exercise for sixty minutes a day, etc.

The genesis of Taubes' book is an article he wrote for the NY Times in 2003. Five years later, Good Calories, Bad Calories was published. As background, there is a video of Taubes here where he overviews his thesis (1 hour 11 minutes, not safe for work since there are pictures of naked obese individuals) and adds a few pieces that were not in the book. Even if you have read the book, I recommend listening to the lecture. You can see from the video, Taubes is very solidly built.

In return for knocking down a bunch of accepted "common knowledge" hypotheses , Taubes presents ten new hypotheses (p.454) and I will add a few more than I extracted from reading the book:
  1. Dietary fat, whether saturated or not, is not a cause of obesity, heart disease, or any other chronic disease of civilization.
  2. The problem is the carbohydrates in the diet, their effect on insulin secretion, and thus the hormonal regulation of homeostasis—the entire harmonic ensemble of the human body. The more easily digestible and refined the carbohydrates, the greater the effect on our health, weight, and well-being.
  3. Sugars—sucrose and high-fructose corn syrup specifically—are particularly harmful, probably because of the combination of fructose and glucose simultaneously elevates insulin levels while overloading the liver with carbohydrates.
  4. Through their direct effect on insulin and blood sugar, refined carbohydrates, starches, and sugars are the dietary cause of coronary heart disease and diabetes. They are the most likely dietary causes of cancer, Alzheimer's diseases, and the other chronic diseases of civilization.
  5. Obesity is a disorder of excess fat accumulation, not overeating, and not sedentary behavior.
  6. Consuming excess calories does not cause us to grow fatter, any more than it causes a child of grow taller. Expending more energy than we consume does not lead to long-term weight loss; it leads to hunger.
  7. Fattening and obesity are caused by an imbalance—a disequilibrium—in the hormonal regulation of adipose tissue and fat metabolism. Fat synthesis and storage exceed the mobilization of fat from the adipose tissue and its subsequent oxidation. We become leaner when the hormonal regulation of the fat tissue reverses the balance.
  8. Insulin is the primary regulator of fat storage. When insulin levels are elevated—either chronically of after a meal—we accumulate fat in our fat tissue. When insulin levels fall, we release fat from our fat tissue and use it for fuel.
  9. By stimulating insulin secretion, carbohydrates make us fat and ultimately cause obesity. The fewer carbohydrates we consume, the leaner we will be.
  10. By driving fat accumulation, carbohydrates also increase hunger and decrease the amount of energy we expend in metabolism and physical activity.
  11. RM: Man, being the premier predator on the planet, evolved to eat a diet high in fat (and in particular the saturated and mono-unsaturated fat found in animal tissue). In the absence of clinical data, we should endeavor to structure our diet to be similar to that we evolved eating, prior to the introduction of agriculture approximately 10,000 BCE.
  12. RM: Advanced Glycation End-products (abbreviated AGEs) may be a cause or byproduct of the oxidative stress that causes aging and many of the maladies associated with it.
  13. RM: A low-calorie, high-carbohydrate diet will make you lethargic as chronically high insulin levels will try to convert glucose to fat while not leaving sufficient calories for the remainder of your basal metabolism. In comparison, low-carbohydrate, moderate-calorie diet will leave you energetic and lean.
One cannot help but wonder how a number of the weak hypotheses that Taubes explores came to become common knowledge in the field of nutrition? Taubes paints a picture of a few egotistical researchers who were able to effect what was essentially scientific fraud, by fitting their bias to the data rather than examining it critically. In Taubes words (p. 451), "it is difficult to use the term "scientist" to describe those individuals who work in these disciples [ed: nutrition, chronic disease, and obesity], and, indeed, I have activity avoided doing so in this book."

More importantly, once they established the common wisdom, they were able to better direct government funding to only support their hypotheses. I came to a somewhat different conclusion to Taubes, in that I see the puritanical aspects of American culture in the formation of these bogus hypotheses. For example, Taubes' quotes Jean Mayer, one of the fieriest preacher that lack of exercise causes obesity, in a 1955 The Atlantic magazine article:
Obesity, it is flatly stated, comes from eating too much and that is all there is to it. Any attempt to search for causes deeper than self-indulgence can only giver support to patients already seeking every possible means to evade their own responsibility.
Like I said, puritanical. This line of thinking can be traced all the way back to people like Sylvester Graham in the 1800s. The idea that cardiac disease might be caused by inflammation and bacterial infection and not by living a sinful life has been remarkably slow to percolate through the American consciousnesses yet it is well understood to be the case now. Obesity is probably not dissimilar.

Prior to my introduction to the world of low-carbohydrate diet, I hadn't paid too much attention to nutritional science. I worked on biophysics, where I formed the opinion that medical science was mostly garbage. This isn't largely the fault of the scientists involved; there's little opportunity for adequate learning though experience of repeated experiments and the systems involved are extraordinarily complex. As a physicist, if I get an correlation coefficient, R2 < 0.9997 in an experiment, I would consider that a poor result. A nutritional researcher working with human patients cannot even dream of achieving the degree of control or characterization I can, and their data are overloaded with spurious noise.

Researchers in the soft sciences typically do not have sufficient math skills to understand the statistical methods that are they are using to evaluate their data. I've lost track of how many times I've seen evaluations of the mean and standard deviation for distributions that are clearly not normal (also known as Gaussian). Don't even get me started on p-values. More importantly, very few medical studies attempt to test a single hypothesis. Far too many studies will compare apples to bananas, rather than apples to no apples, or they'll compare apples, oranges, and bananas to no fruit. Making conclusions from such messily designed experiments is rife with the potential for misinterpretation. Drug studies are often an exception.

The Insulin Hypothesis

The central thesis of "Good Calories, Bad Calories" is that chronically elevated insulin levels is likely responsibly for the, "diseases of Civilization," such as diabetes, heart disease, cancer, etc. I put, "diseases of Civilization," in scare quotes because although these diseases are absent from primitive cultures, it is obnoxious to explain to individuals of non-Western ancestry that they do not suffer from these diseases because they are uncivilized (Burkitt and Trowell). Wikipedia calls these Lifestyle diseases, which seems a more apt terminology.

Let me be clear: nothing about Taubes' insulin hypotheses are actually owned by Taubes. The idea that carbohydrates are fattening has been known from well before the discovery insulin. The knowledge that diabetes could be cured by avoiding carbohydrates was also known before the discovery of insulin. Taubes is merely going over old research and bringing it together as a strong argument.

When viewed through the prism of evolutionary science, this makes a lot of sense. Fat stores would have been necessary to maintain the organism when hunting failed and there were insufficient edible plants. Carbohydrate stores, on the other hand, requires a huge amount of water to act as solvent. Each gram of glycogen that you store needs ~2.5 g of water solvent, so at 4 kcal/g carb, you have an effective storage capacity of 4 kcal/3.5 g = 1.15 kcal/g. Fat is 9 kcal/g and it doesn't require a solvent when stored in adipose tissue so that's a 7-fold increase in storage capacity. Fat is a vastly superior way to store energy.

So what was the source of carbohydrates for humans before we developed agriculture? Presumably wild fruit. Fruit matures, more or less, all at once as anyone who has owned an apple tree knows, and rots rather quickly after it has fallen off the tree. Thus, when fruit is available, it is perfectly logical to gorge oneself and use all that easily harvested sugar energy to synthesize fat storage for consumption in lean times. Thus the evolutionary reason for our sweet-tooth is easily explained.

Effectively, we evolved to preferentially burn-off the glycogen in our muscles and liver before we switched to fat. There's ~300 g of carbohydrates stored in the body, which corresponds to ~1500 kcal. Just you try and burn 1500 calories via a cardio-workout. Eating three square meals a day with carbs at every serving implies that you will never burn through your reserves and hence the body will never resort to burning fat.

So, briefly, how does one use these conclusions to achieve a healthy low body fat (and BTW, waist circumference is the #1 metric for heart disease)? Certainly not by the standard, low-calorie, high-carbohydrate diet (semi-starvation diet in Taubes' terms) which has been nothing but a dismal failure from a clinical and practical perspective. There are three basic strategies:
  1. Very long and very slow exercise (4+ hrs), typically hiking or cycling in my case. This is a far cry from the type of anaerobic-limit cardio exercise one typically sees recommended, for example, by the American Heart Association. There is a yawning gulf between walking and jogging. I personally approve of anaerobic exercise, such as sprint intervals or plyometrics.
  2. Consistently eat carbohydrates at a low enough level that the brain (which prefers glucose over ketones) consumes the entirety of carbohydrates that you eat, leaving the body to burn ketones. This is a slow process.
  3. Periodically fast for an extended period of time so that your basal metabolism burns through your glycogen reserve and then begins to mobilize fat. This is not a calorie reduction method, rather you are simply not eating three times a day (on average), and as such having more extremely calories negative and calorie positive periods.
Eventually, everyone will plateau at a certain level of body fat. The number of fat cells in your body is more or less set by age twenty; dieting simply changes how full they are. Eventually, fat cells will revolt and through leptin demand a stronger appetite. So is there any need at all for carbohydrates in the diet?

Grains are the ultimate, "empty calories," in terms of micronutrients. Not only to grains have essentially no micronutrients (they are fortified for a reason), they also have a number of anti-nutrients that impede the uptake of nutrients from vegetables and animal tissue. From a health perspective, there's no need to eat grains or starchy vegetables such as potatoes.

Typically one might recommend 50-80 grams per day simply to supply the brain with glucose, but even this is not strictly necessary as the liver can convert fatty acids to glycogen. Of course, people who are obese are likely suffering from hyperinsulina (insulin resistance/metabolic syndrome) and as such may suffer discomfort upon undertaking an low-carbohydrate diet.

For the record, I dropped 22 lbs. (20 lbs. by August 2008) going from a BMI of 24.7 in May 2008 to 21.4 as of now. I've been as low as 143 lbs. in the past but I was never able to maintain that; typically I got to such a weight by bicycling 12+ hours a week at 30-40 km/h. I'm now sitting at 145 lbs. (edit: now 144 lbs.), in January (ed. February), in Edmonton, with no chronic cardio. This is a totally new scenario for me as I almost always put on 10 lbs. over winter.

When I put on weight it is prominently in the form of visceral and subcutaneous fat; I've never had significant interstitial muscular fat so I've always had relatively hard muscles. I try and aim for a distribution of 60 % fat, 25 % protein, and 15 % carbohydrate in my diet. Since my blood sugar/insulin isn't riding a roller coaster up and down throughout the day, I generally don't get hungry. I am much better at concentrating throughout the course of the day, irrelevant of when I last ate and I've found that my thinking process is much cleaner and crisper.

Unanswered Questions

Taubes criticizes a number of scientists in his book for over-simplifying the science of physiology in an effort to understand it. In that respect, reducing the argument of "Good Calories, Bad Calories" to carbohydrates-bad, fat-good is probably guilty of the same offense.

Taubes dose throw us a couple of bones, in the form of some of the more buzzword lines of research in nutrition today. One is Advanced Glycation End-products (AGEs); we know that AGEs are tightly correlated to age. From what I've read, thus far the early reports on AGEs are similar to those on cholesterol fifty years prior: lot's of smoke, but no fire. Efforts to link AGEs to ingestion of AGE materials (e.g. burned meat) has thus far failed, IMO.

Fat-soluble vitamins

One aspect of carbohydrate/fat balance that Taubes does not cover is the impact of the fat-soluble micro-nutrients. We, as humans, have given up our abilities to fabricate the majority of vitamins that we need in favour of having big brains. We are very poor at transforming one complex of a vitamin (typically the vegetable source) to the type we need to function.

As our consumption of fats has declined in favour of carbohydrate the quality of fats that we eat has also declined. As such, we are typically deficient in fat soluble vitamins, in particular D3 and K2. Not only we as a society getting far less vitamin D3 from sun exposure, but the animals we eat are also more often than not locked in a barn eating corn, so they also contain less fat soluble vitamin. When you consider that your skin can produce something like 10,000 IU of D3 in an hour compared to a multivitamin at 400 IU, it's not a giant stretch to believe that the majority of Western people are going through life deficient in it. K2 is similar; butter is a good source, but butter has been demonized by our corporate media.

Poly-unsaturated Fats

Palmitic acid is the fatty acid that your liver manufactures from sugars. In fact, the only fat humans evolved to burn for fuel directly is saturated fat. All other fats we trans-saturate first, and then burn. It would seem strange then given the complexity of the human body that we evolved to preferentially make saturated fats over polyunsaturates, unless we prefer saturated fat because it is more stable and hence less prone to oxidation.

The canard that saturated fats, "clog your arteries," is just that, bogus. The medical establishment has never believed this since they knew full well plaques form inside the arterial wall, not on the surface. Why this idea was allowed to percolate through the public, I do not know.

This begs the question, should we eat polyunsaturates at all? They are, after all, highly unstable and very easily oxidized. I ask a question: when was the last time you bought a nut oil, e.g. walnut or sesame, at the supermarket? Was is refrigerated on the shelf? Was is in a brown bottle to prevent light from damaging the polyunsaturated fat? I've seen flax oil sold in such a fashion but no other. Much of the fat we eat is oxidized by the time it reaches our mouths.

Fish oil (omega-3) is clearly doing people a lot of good, even if it sits in a cylinder for months. A lot of people do feel that we get far too much Linoleic acid, an Omega-6 essential pre-cursor, from soy, corn, safflower and other vegetable oils. It does, after all, have a significant hormonal effect.

This has led some to suggest that one should balance omega-3 and omega-6 consumption. I.e. if your omega-3 consumption is 3-4 one gram capsules of fish oil a day, then you shouldn't eat more than ~5-10 grams of vegetable oil. The American Heart Association apparently felt the need to push out an editorial recommending that the diet 5-10 % of calories should be in the form of omega-6 polyunsaturates to counter this meme. The fascinating thing about this editorial is that there are 81 references in 3 pages (which is beyond extreme), yet, there are no references — no studies, no research — that support the advised level of dietary intake. Take a look at the article (it's free access), it's quite amazing.

Rebuttal: Conservation of Energy

One of Taubes' chapters deals with the idea that energy balance in humans can be reduced to the First Law of Thermodynamics:
ΔE = Ein - Eout
I was somewhat confused to see this Surely the nutritional scientists did not not really believe this, right? I mean, any idiot undergraduate students knows that the 1st Law is only useful in a closed system, and humans live on the planet Earth, not in an insulated box. Right?

Enter a rebuttal by G. Bray in the journal Obesity Reviews. Bray is a to be a major obesity researcher and one of the 2nd tier villains in the book. Taubes relates a story of Bray excising a section of a British report on obesity, where Bray removed the material pertaining to the relationship between insulin and obesity. He clearly has editorial support to make his case. Bray is one of the second-tier villains in Taubes' book. Taubes has a footnote (p. 421), which suggests that Bray actively suppressed the carbohydrate-insulin hypothesis.
* According to Novin, when he wrote up his presentation for the conference proceedings Bray removed the last four pages, all of which were on the link between carbohydrates, insulin, hunger, and weight gain. "I couldn't believe he would make that kind of arbitrary decision," Novin said.
Unfortunately, to a physicist this energy balance hypothesis looks like a silly hand-waving exercise, not a serious argument. Frankly I was flabbergasted when I first read this article. This conservation of energy argument is on the same scientific level as the ridiculous "drink cold water to lose weight" idiocy. A human organism is:
  1. Not in thermal equilibrium with their environment. Last time I checked I have a body temperature around 38 °C and spend most of my time in 21 °C rooms.
  2. Capable of significant mass flows (e.g. respiration).
  3. Capable of sequestering entropy (e.g. protein synthesis).
Is wearing a sweater fattening (by insulating you from your environment)? Here's a quote from the rebuttal,
Let me make my position very clear. Obesity is the result of a prolonged small positive energy surplus with fat storage as the result. An energy deficit produces weight loss and tips the balance in the opposite direction from overeating.
According Bray's thermodynamics argument, wearing sweaters makes you fat. This illustrates the greatest fallacy of trying to apply the 1st Law to a human: it makes the implication that living organisms consume kilocalories for the purpose of generating heat rather than perform useful work (i.e. breathing, contracting cardio and skeletal muscle, generating nervous action pulses, etc.). In reality heat is the waste product of basal metabolism. The first law does not distinguish between different types of energy. Heat, work are all equal under the First Law of Thermodynamics.

Applying the 1st Law to living organisms is Proof by Tautology. Yes, 1 + 1 = 2, but this tells us absolutely nothing about the underlying mechanics. The 1st Law does not (I repeat N-O-T) tell us whether you store excess energy in the form of fat, or bleed it off into the atmosphere by dilating blood vessels next to the skin, sweating, etc. To do so would require an accounting of entropy.

What would a semi-rigorous description of the thermodynamics of a human organism look like? Look at the title strip on the top of the page. See that equation in the background?

This type of equation would be a bare starting point for energy balance in a complex system like a living organism. Good luck actually accounting for all the terms. Those Σs are sums.

If anyone else has seen any other critical reviews to "Good Calories, Bad Calories," please feel free to post them in comments and I will take a look.

Environmental Aspects

As most people are aware, feedlot meat production produces copious amounts of greenhouse gases, both in terms of the fertilizer required to grow the corn to feed the animals, and the methane produced by rudiment digestion. This provides a bit of a moral quandary, in that feedlot meat is not readily described as sustainable.

First, greenhouse gases are perfectly fungible, so since my personal greenhouse gas emissions are about 1/3 normal, I am still well under any proposed quota. Although this has an aspect of the "beer refrigerator paradox" to it, it's still valid if the numbers work out.

Second, as it happens, I do live in Alberta and I can and do buy pasture-raised meat. Meat that feeds on unfertilized prairie grasses not only has a different composition but a far lower greenhouse potential. The visual difference between feedlot beef and pasture Elk is fairly startling. About 50 - 65 % of what I buy is via individual farmers at the market. In particular, I try to ensure that all the offal (organ meats) that I buy are from pastured, hormone and antibiotic-free animals since they are more likely to concentrate in the organs.

It's true that if everyone tried to by pasture-fed meat, there would not be enough to go around, but at the moment it is sustainable for me.

42 comments:

VV111y said...

Hi Rob,

Great blog btw.

This sounds like 'evolutionary fitness' - also see 'paleolithic diet'.

I don't know who started this, but I believe one of the main proponents is Arthur de Vany. He is now 70 and has been living this way most of his adult life, so I assume he is the originator. You can google for his blog and other info. At his age he claims to use no medication, is still very active, and has pretty much no health problems.

It's interesting, and I'm gravitating over to that lifestyle myself.

Do you know if any of the farmers in your area could ship to Ontario?

Regards,
Will

Robert McLeod said...

V:

Yes I'm familiar with that area. The idea that one should use evolution as a life guide didn't originate with Cordain or de Vany, however. If I had an electronic copy of Good Calories, Bad Calories, I could track down the cite but people were suggesting this back in the twilight of the British empire. I seem to recall it was with regards to the British doctors who coined the term saccharine disease.

de Vany's webpage is closed of course, which greatly curtails his influence, but I seem to recall him being against the concept of homeostasis. I.e. he was on Bray's side of the fence. He just tried to show that eating intermittently should induce a negative energy balance.

If I'm going to send anyone anywhere for diet advise, I would suggest:

www.marksdailyapple.com/

and for a more technical approach

/wholehealthsource.blogspot.com/
One can spider out via links from the above two sites.

Frozen meat isn't exactly something you can ship by Canada Post. Unless you live in an apartment in the middle of Toronto, I think you can still find great farmers markets in Ontario. I know the middle of Ottawa has a giant one, for example. Ontario is really more temperate than Alberta and still is an agricultural powerhouse.

VV111y said...

Yeah, I keep up with Mark's daily apple occasionally.

I'll check out the other link, thanks.

For the meat, I can probably find something in the area, but it's good to have more options. ex. there's a game meat farm close by, and while they don't use any hormones, they do use antibiotics/meds... and they're pricey to boot.

DeVany says pretty much the same things as Taube, marksdailyapple, etc. He goes on about power law principles in everything from diet to activity. so yeah, he has intermittent fasting, random diet patterns, random, occasionally intense activity, etc. He does have a new site up, and seems to be trying to make money off this.

Didn't know about the history - I don't know who Cordain or Bray are. Thanks for the info.

Robert McLeod said...

No, de Vany is very much on a different side of the fence as Taubes. Maybe he's changed his mind, but his paper on power-law eating specifically

Why We Get Fat

I argue that there is no adaptive value in maintaining energy balance in the world of our ancestors and that human metabolism and feeding are not energetically balanced. Homeostasis in energy intake and expenditure and energy stores is not adapted to a complex energy environment. Humans, and other mammals, are “designed” to feed in excess of energy expenditure. Our evolved instincts are to live in a state of positive energy balance in which we eat too much and exercise too little. This energy bias was adaptive in the world of our ancestors where high energy expenditure and food procurement were intermittent and insecurely linked to one another.

But it's really, really hard to get fat on a zero-carbohydrate diet. You just don't have the appetite. Maybe de Vany has changed his mind since Taubes published, I don't know. I do agree that de Vany is more thinking than the conventional establishment, but I still think he's right for the wrong reasons. The joke with economists is they develop one idea (a hammer, or in this case a power law) and apply it to everything (Look nail!, nail!, and another nail!).

Bray is the gentlemen I discussed in the conversation of energy portion of my post. He represents conventional obesity thinking (a calorie is a calorie).

Robert McLeod said...

A tag ate some of my post there.

Maybe he's changed his mind, but his paper on power-law eating specifically argues against homeostasis and for the energy balance argument.

Krassen Dimitrov said...

Great post, as always, Robert. Couple of questions:

1. What about stress? This seems to be a predominant theory these days and one that may have little to do with the equilibrium metabolism that you talk about.

It posits that the high levels of stress hormones increase cravings, and hence overconsumption ("comfort food"), beyond the ability of the body to dispose of it. If that theory has substance to it, the First Law is perfectly applicable:

a) you consume more than the body's capacity to dispose of (you can't raise your temperature and you can't evaporate profusely or you'll look like a steam engine)
b) NOT consuming these extra "comfort" calories, by resisting your cravings, would get you back to equilibrium where First Law is not as critical (or as you say, in that regime any drop in consumption is countered by slowdown in evaporation, lethargy, etc. to conserve body mass.)
c)the role of exercise, in that theory, is not so much to burn calories, as with this stress-related overconsumption you would need to be on a treadmill 24 hr/day, but more to reduce your stress level to regulate your appetite.
d) unless you are really, really short, at 145lbs you likely have never been in that overconsumption regime. I, on the other hand fluctuate between 200-220, and have noticed that if I don't exercise and get back home wound up from work I am capable of devouring a lot; on the other hand even a short 20-min workout seems to moderate my appetite.

2. Why do you say greenhouse gases are perfectly fungible? I believe they are only partially fungible and have speculated a bit on that:

http://algae-thermodynamics.blogspot.com/2008/12/algae-in-desert.html

Robert McLeod said...

Krassen Dimitrov said:
Great post, as always, Robert. Couple of questions:

1. What about stress? This seems to be a predominant theory these days and one that may have little to do with the equilibrium metabolism that you talk about. It posits that the high levels of stress hormones increase cravings, and hence overconsumption ("comfort food"), beyond the ability of the body to dispose of it. If that theory has substance to it, the First Law is perfectly applicable:


I believe that stress and the associated cortisol response is a subset of inflammation. However, I now believe that the majority of inflammation is a result of diet. If you look at the substances that cause people the most problems with intolerance/allergy, they are all eliminated on a low-carbohydrate diet: wheat (gluten), milk (casein), and legumes (including peanuts). All of these products can elicit an auto-immune response to reject the small intestine and hence are massive sources of inflammation in a large minority of the population. One topic I didn't discuss is the anti-nutrients found in many vegetables. Anti-nutrients are compounds that inhibit the uptake of micronutrients. Examples would be the lectins in grain, oxolate in spinach, solonane in tomatoes/peppers/potatoes, etc. Most plants evolved defenses against animals eating them. We’ve breed a lot of those characteristics out, but plants still often require extensive treatment to make them digestible.

If you read up on cortisol you'll quickly realize how closely linked it is to the dietary process. A good place to start on the inflamation theory is probably Chris Masterjohn's webpage:

High Cholesterol And Heart Disease — Myth or Truth?

And the tabs at the top of the page.

a) you consume more than the body's capacity to dispose of (you can't raise your temperature and you can't evaporate profusely or you'll look like a steam engine)
b) NOT consuming these extra "comfort" calories, by resisting your cravings, would get you back to equilibrium where First Law is not as critical (or as you say, in that regime any drop in consumption is countered by slowdown in evaporation, lethargy, etc. to conserve body mass.)
c)the role of exercise, in that theory, is not so much to burn calories, as with this stress-related overconsumption you would need to be on a treadmill 24 hr/day, but more to reduce your stress level to regulate your appetite.
d) unless you are really, really short, at 145lbs you likely have never been in that overconsumption regime. I, on the other hand fluctuate between 200-220, and have noticed that if I don't exercise and get back home wound up from work I am capable of devouring a lot; on the other hand even a short 20-min workout seems to moderate my appetite.


I agree that I'm not in the same situation as people who are already overweight and pre-diabetic. I did make a throw-away reference to insulin resistance (hyperinsulinemia, although I misspelled it as hyperinsulina). What I was trying to imply there is that, if you have chronically high blood glucose resulting in your body's tissues being insulin resistant then you will have a harder time breaking the addiction to sugar and switching to a fat-based metabolism.

Let me offer an alternative explanation to your symptoms: I hypothesize that appetite is controlled by blood glucose levels (and hence insulin). Appetite is greatly reduced by having low blood glucose (somewhat paradoxical, but read Taubes' book). When you exercise, you deplete the glycogen in your muscles. Hence, the muscle tissue becomes less insulin resistant, and absorbs glucose from the blood, thereby reducing blood glucose levels to the point where you are no longer having cravings for sugar (comfort food being a synonym for sugar and starch). The satiety induced by a high-fat, high-protein, low-carbohydrate diet has to be experienced to be believed.

So yes, exercise in your case may be treating the symptoms that you are experiencing. However, it is not treating the causation of the problem: too much glucose in the diet, leading to chronically elevated blood glucose levels.

FYI, I'm 175 cm/5'9" tall, and in the course of dropping my overall body mass by 16 % I've definitely gained a few pounds of protein. Anecdotally, I experience far less anxiety under a high-fat diet compared to a high-carbohydrate diet. It does take some time to transition from being a lipidophobe to a lipidophile, but eventually you pick the pork shoulder roast over the leg roast and enjoy it.

2. Why do you say greenhouse gases are perfectly fungible? I believe they are only partially fungible and have speculated a bit on that:

http://algae-thermodynamics.blogspot.com/2008/12/algae-in-desert.html


What's the half-life of CO2, 330 years? Methane is 7 years? The article you cite suggests that CO2 concentration falls off from 550 ppm in the city core to 370 ppm in the suburbs. That's a pretty steep gradient, which implies diffusion is rapid on the timescale of years.

Stephan said...

Robert,

I tried responding to your e-mail today but it bounced back repeatedly. Is something up with your e-mail service?

Don said...

Provocative blog. Looks sound on the diet/obesity issues. It is a stretch to say the carbohydrate/insulin drive cancer risks overall....could be true for some fraction of certain cancers such as colon, breast, prostate but is likely almost entirely irrelevant to smoking-related cancers, esp. those such as lung cancer that is almost entirely attributable to smoking.
Don Wigle (a patient of your father here in Ottawa...and a medical epidemiologist)

Robert McLeod said...

Don:

Thanks for the comment. That is Gary Taubes' hypothesis, not mine. I would agree that carbohydrates are not a likely cause of cancer.

However, I think I would be comfortable stating that cancer cannot grow effectively without a supply of glucose. The fermentation metabolic pathway cancer uses allows it to consume an enormous amount of glucose, but it is highly inefficient. The uptake of glucose is so strong that Positron Emission Tomography (PET) scans use radioactively labeled glucose to local tumors in the human body. Starving a malignant tumour of glucose would seem to be an obvious strategy to restrict its growth.

Here is an example of research on the topic:

Targeting energy metabolism in brain cancer with calorically restricted ketogenic diets.

A diet resulting in low serum insulin and hence low blood glucose levels should be a gimmie for any cancer treatment. Fasting could also be introduced to further enhance glucose sensitivity, although doing so would also boost human-growth hormone and testosterone production. The objective would be for people to die with cancer, and not of cancer.

Richard Nikoley said...

Regarding fasting and cancer, there's another reason to fast:

http://www.physorg.com/news126202490.html

It seems that fasting for a couple of days puts non-cancerous cells into a protective posture, whereby you tip the chemo war of attrition from 1-1 to like 5-1 and more.

Quite interesting reading.

Just found your blog, Robert, on the heals of that comment you dropped at my place the other day on the K2. Thanks for getting Stephan that study. As you may know, he has posted hi analysis.

Travers said...
This comment has been removed by the author.
sector7agent said...

Nice review.

I'm sure I missed something in your discussion regarding the first law. You say, "This illustrates the greatest fallacy of trying to apply the 1st Law to a human: it makes the implication that living organisms consume kilocalories for the purpose of generating heat rather than perform useful work". But then you grant that, "Heat, work are all equal under the First Law of Thermodynamics." So applying the law can not imply that heat is all that matters.

Also, the majority of energy used by warm blooded animals is used to regulate body temperature. As heat dissipates to the environment, the organism adds heat by consuming stored fuel. A sweater would reduce the heat addition required to maintain a constant temperature in a cold room. This is not the same as saying, "wearing sweaters makes you fat". That smacks of strawman fallacy.

Robert McLeod said...

Sector7Agent:

The sweater argument is supposed to be fallacious and is intended to illustrate that the energy balance -> fat hypothesis is also fallacious.

Let's construct another example, using the the conservation of mass.

delta(m) = m_out - m_in

So let's say I gain 2 kg of body mass. Based on the law of conservation of mass, did I:

A. Increase water retention?
B. Gain lean body mass?
C. Gain fat?
D. All of the above?

Please let me know, on the basis of conservation of mass, which of the four answers is correct.

I disagree that the majority of calories consumed are burned for the purpose of generating heat. We do have methods of burning calories solely to produce heat (i.e. shivering, brown adipose tissue) but these two mechanisms constitute only a small part of of our total calories, normally. Regulation of temperature is primarily done by controlling the dilation of capillaries near the surface and sweating.

Heat is the waste product of the exergy we consume to perform useful work. We ingest chemical potential energy in the form of food. That potential energy is then transformed into useful work (contracting a muscle, firing a neuron, operating ion pumps in the liver, etc.). Then, through friction forces, that useful work is dissipated into heat. Each time we cross from one form of energy to another, chemical potential -> work -> friction, entropy is generated which ultimately results in our need to get rid of the waste heat as a by-product.

Robert McLeod said...

I should probably add mitochrondial decoupling in muscle as another possible source of pure thermogenesis:


Human Skeletal Muscle Mitochondrial Uncoupling Is Associated with Cold Induced Adaptive Thermogenesis


Some interesting quotes:
The increase in energy expenditure, 0.32 MJ/day (−0.20 to 1.66 MJ/day), is comparable to data from literature [9], [14], [15]. This increase is considerably smaller than the increase in energy expenditure observed in small mammals after cold exposure (two- to fourfold) [16].

320 kJ is about 75 kcal. Also,

The increase in TDEE was not explained by increased physical activity: in fact mild cold exposure resulted in a significant decrease in physical activity (−39 kcounts/day, z = −2.67, p<0.01) (figure 1b).

TDEE is total daily energy expenditure.

Richard Nikoley said...

That's pretty interesting, Robert.

Let me relay a self-experiment (among many) I did some months and a little over 10 pounds ago.

http://www.freetheanimal.com/root/2008/08/the-hunger-returns.html

In case you don't want to read the whole thing, here's the meat of it. This happened at about 10 hours into what was to be nearly a 36-hr fast.

"Now for the next experiment, which I mentioned back at the beginning. I went down to the gym for a simple sauna, steam bath, Jacuzzi, and then the cold pool. As I said: I was hungry and wanted some enjoyable activity to get my mind off it. I spent about 10 minutes or so in the sauna, just a few in the steam room (now I'm really pouring sweat), then into the Jacuzzi. The reward for all that torture (it's really stressful, for me) is the cold dip, which they keep around 50 degrees or so. I go in after the workouts because it's like an energy reset button. I've worked myself up from about 30 seconds to now bouts of 5 minutes or so. That's what I did yesterday, but even longer. I stayed in until I had a pretty violent shiver going, then I got out, took a cold shower, and went home.

Before I did, I weighed myself at 199 (after the sweating). I remained a bit chilled for quite a while, but then noticed something: no hunger. Not at all. Then, 11pm rolls around and I hit the sack. Slept great for eight hours, got up for the customary 3.5 mile walk, and I'm still not hungry. Not at all. I go home, got ready to shower, and stepped on the scale for a big shocker: 194. I had dropped 5 pounds in a matter of hours. And, it's now 1:30pm (when I began this post), 28-hours into the fast, and just now the hunger begins to return. I've got to suspect the ice-cold water to the point of a pretty good shiver for both the unusual lack of hunger and the extreme weight loss. I'll have to see if I can duplicate on the next fast."

I still can't be sure it was the cold that cause that rapid, huge weight loss, and I'm very low carb all the time (and fast 24-30 hours twice per week), so it's not like I'm loaded with glycogen and it's associated water.

What do you make of it?

Robert McLeod said...

Richard:

I don't think 5 lbs. is out of line if you've been sweating and fasting. I think the most weight I've ever lost in a day was 12 lbs. in the summer when I was out playing all day. I was dehydrated for sure, but it shows just how much water and salt reserve we carry.

sector7agent said...

Regarding "The sweater argument is supposed to be fallacious and is intended to illustrate that the energy balance -> fat hypothesis is also fallacious": Intended or not, a fallacy is an argument that is not logically sound.

Regarding "I disagree that the majority of calories consumed are burned for the purpose of generating heat": I said, "the majority of energy used by warm blooded animals is used to regulate body temperature". You disagree with a statement that you made (again a strawman). Just the same reference
http://en.wikipedia.org/wiki/Warm-blooded:

"Also, the energy required to maintain the homeothermic temperature comes from food - this results in homeothermic animals needing to eat much more food than poikilothermic animals.

Shivering and fat-burning to maintain temperature are very energy-intensive, for example:

in winter many small birds lose one third of their body weight overnight.
in general a warm-blooded animal requires 5 to 10 times as much food as a cold-blooded animal of the same size and build, so cold-blooded animals are better at surviving in barren environments."


David

john92862 said...

Robert,

A great article. One other big reason low carb high fat diets do not make you fat - it takes a lot of energy to simply digest fat and proteins. Sugar and carbs are easily digested and convert almost 100% into fuel. So the speed, and efficency, of which carbs and sugar are digested makes them particularly prone to be converted into fat.

Anonymous said...

You're a fucking idiot.

nfiertel said...

You have done your readers a service in reviewing Taube's book. When I try to explain to people about true research vs the bullshit assumptions and presumptions of the so called nurtritional experts people say, sure..sure..and is that why you wear extra large? Nonetheless, the primal diet makes sense from an evolutionary point of view and I have not seen any improvement in either societal weight gains through dieting or changes from fat to carbs....I suspect however that there is an increase in macular degeneration from the lack of lutein from not eating eggs for example and whatever increase in heart health I bet is more to do with taking lipitor than not eating a nice steak. One needs to eat fish and meat and veggies and roots and skip the grains..oh yes, eat those nuts of course...whatever grows that one can pick or hunt covers it pretty much..I remember being given this disgusting inedible diet by an expert in nutrition..so called...I tried eating using it as a guide..I realised in about a day that it was terrible and I lasted a month, had a headache the entire time, could do not creative work and was not a nice person to be around instead of my joyous and wonderful normal self ( irony here?) I went back to eating..human food. I am still here on this earth. I am nearly 68. All life is gravy when one reaches past 60 so long as one leaves the flour out of it.. I asked my doctor about dieting. He asked me if I ever knew anyone who kept off weight. The answer is no. Indeed said my doctor.

SnowDog said...

Cows cannot contribute to global warming, since the carbon that they are emitting into the atmosphere, is in balance with the carbon they eat, from plants which pull the carbon from the atmosphere.

An increase in CO2 in the atmosphere, over time, can only come from pulling the carbon out of the ground in the form of oil, coal, and natural gas, where it has been sequestered for millions of years.

Robert McLeod said...

john92862:

I think fat is actually the most efficiently metabolized food, at about 3 % losses, followed by carbs at around 10 %, and protein is around 30 %. Protein is known to be

I think glucose proper is probably not quite the same thing as sugars that include galactose or fructose. Pure glucose should be digested and metabolized very efficiently. But so are saturated fats.

Anonymous:

Belittling me only reinforces my position to an outside observer. Learn how to argue.

nfiertel:

Yup. Top-down, observational nutritional science has been a dismal failure.

SnowDog:

Cows do produce quite a lot of methane which might otherwise be sequestered underground. Animals are required to work in synergy to grow rich, thick soil, however. Anyone who's ever walked through a cow patty will understand this intuitively.

The bigger issue is probably the urea fertilizer used to grow the corn which is used to finish the cow. Of course, that's not necessary (neither the urea nor the finishing).

Agriculture and greenhouse gases is an immensely difficult problem to analyze. Is grass-fed, local Alberta beef less CO2 intensive that Chilean fruit? Probably.

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Matt said...

You realize that your statement that the body isn't in thermodynamic equilibrium is a red herring at best and a strawman at worst, right?

Phrased differently: where are all the fat people dying from starvation?

If I give a starving Ethiopian a single insulin-stimulating meal of CHO only, will he suddenly get fat?

That's where your argument leads logically. You're implicitly suggesting that someone can simultaneously be fat and yet dying of starvation from nutrient deficiency.

Like it or not, the body does do book-keeping based on calorie intake. Our bodies are still enclosed in a membrane separating us from the environment; energy still has to flow across that membrane.

Your objections are a red herring distracting from the fact that energy losses via feces, sweat, radiative heat, and anything else still effect the "calories out" side of the equation.

It's still energy that has to be accounted for via feeding.

If you want to show me some fat starving people to say otherwise, by all means let empiricism prove me wrong.

Daniel said...

Hey Matt,

Your body is not a cash register. It only cares what you ate at your LAST meal. I can eat a huge pizza at one meal and get fat. Spread those carbs out throughout the day and you won't get fat! You can find more info about this on YAHOO!

Good luck.

Muhammad said...

A critical review of Good Calories Bad Calories:
Book: Cholesterol Wars by Daniel Steinberg

I didn't read the whole book yet, but it's an interesting scientific book that tries to argues for the Cholesterol-Hypothesis

it's the only one I found so far. I am waiting for a response y Gary Taubes to this book.

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Jim Purdy said...

I've been reading Gary Taubes' GCBC, and it has really changed my thoughts about my diet.

Today, I've been experimenting with a short-term high-fat diet of what I call "Buttery Broth."

I start it with a bowl of hot water, to which I add one-fourth stick of Land-O-Lakes unsalted sweet butter (200 calories, all fat), one packet of Herb-Ox sodium-free chicken bouillon (10 calories), and one cube of Wyler's instant chicken bouillon (5 calories).

The result is a tasty high-fat buttery chicken broth with 215 calories.

Any comments on whether that is a good or bad food item?

Term said...

Thanks for pulling this together and sharing..!





Term papers within deadlines.

Razwell said...

So the calorie theory of fat loss is wrong as so is Lyle McDonald?

If so how do you lose fat?

danh said...

I was wondering if you've ever come across Matt Stone's blog, particularly this entry on Taubes:
http://180degreehealth.blogspot.com/2009/07/low-carb-oops.html
He's one of the few people besides Stephen and Petro from wholehealthsource and hyperlipid blogs to realize that it's not just the carbs drives insulin drives fat theory. He has a more broader look of the hormonal and metabolic system especially the thyroid and the adrenal glands, taking into account research not just by Weston Price and Steffanson, but also by Mccarrison, Broda Barnes, TJ Cleave, and Melvin Page.

Do you have any thoughts on this or these scientists?

Robert Zemekis said...

Great story.. Yes, it seems that we should talk about healthy eating instead of bad or good calories. Anyway the purpose of any diet is to move your eating habits to new healthy level. Thanks for sharing and possibility to comment! Welcome to visit Ideal Weight Blog to find some recipes and great articles! Thanks!

Apolloswabbie said...

Great post, thanks. In the best blogs, I've found I get as much from the comments as from the posts.

You asked about other critiques of Taubes - this one isn't all that serious, http://www.thebsdetective.com/2009/10/bullshitter-of-day-oct-7th-gary-taubes.html, but I think it's typical of the profession. How eager are the nutritionists going to be to fess up when they realized they've been killing people?

My rebuttal of Mr. BS, mostly of value for those not familiar with Taubes' perspective, is here: http://fireofthegodsfitness.blogspot.com/2010/04/review-of-critique-of-gcbc-carbohydrate.html

Apolloswabbie said...

Matt, you miss the point. As the pizza commenter points out, if your starving ethiopian eats a high carb meal, especially given the exquisite insulin sensitivity of the truly starving, much of that food will be converted to fat. If insulin levels are high enough, that 'starving' person will be unable to access that stored fat until the blood levels of insulin fall. At the cellular level, your 'feasting starving person' will have the same problem as the non-feasting starving person - low energy availability, and thus the body generates many of the normal physiological responses that result from low energy availability at the cells. Now take the normal obese American, but make it a poor American doing manual labor ... they are working a lot, thus need energy, but cannot get it from stored fat due the action of the 'carb-insulin' cycle they sustain. This person will be hungry, and will eat what any poor person eats, CARBS! They are cheap and readily available, and sustain the 'carb-insulin' cycle. Our poor, fat, manual laborer won't literally starve to death because they eat all the time, but at the cellular level, the body gets brief periods of energy until the insulin drives the energy into fat cells, and at the same time, prevents liberation of stored fat. Right back to cellular starvation, hunger, etc.

If you really care to understand this, read GCBC; at least then you would be informed enough to mount a significant critique, even if you still choose to believe 'a calorie is a calorie.'

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