Good Calories, Bad Calories: A Critical Review; Chapter 24 – The Carbohydrate Hypothesis III: Hunger and Satiety

cover

Introduction

This is another post in my ongoing series of posts on Gary Taubes’s Good Calories, Bad Calories (GCBC). One of the main challenges I have encountered while reviewing this chapter is that Taubes devotes several pages to discussing the work of Jacques Le Magnen and attempting to associate Le Magnen’s research with Taubes’s own theories. My undergraduate advisor actually spent some time in France and worked directly with Le Magnen, so of course all his students were educated on Le Magnen’s work. However, Taubes cites a number of texts by Le Magnen that I was either unable to find or are written entirely in French. For that reason I cannot comment on the specifics of the texts, and unless I find some of the specific texts Taubes cites these pages are outside the scope of this chapter review.

Not the Introduction

On pages 425-426 Taubes describes a diet that was designed by JB Sidbury and RP Schwartz to help obese children lose weight, stating “The diet that Sidbury eventually used in his clinic and claimed to be uniquely effective contained only 15 percent carbohydrates-‘the remaining being apportioned approximately equally between protein and fat […]’” Taubes makes great hay of Sidbury’s diet and how it reduced insulin levels and therefore fat mass, stating also “insulin will ‘facilitate lipogenesis’ and inhibit the release of fat in the adipose tissue, this in turn created what Sidbury called the ‘milieu for positive fat balance’ in the cells of the adipose tissue” and “’decreased insulin levels would then permit normal fatty acid mobilization’” and “he [Sidbury] described an approach to obesity therapy that differed from Robert Atkins’s only in the details of the application.”

Leaving aside that Sidbury and Schwartz never claimed their diet was “uniquely” effective, they do claim that their dietary treatment was effective to some degree, which is really no surprise if you read the details of their diet.1 From page 67 of Childhood Obesity:

Prior to our interest in the subject, we routinely had the dietitian give the mother a 1000 calorie diet for an obese child, whether 4 or 14 years old. The results could have been predicted with a little reflection. Indeed an adult should be given a 700 or 800 calorie diet if weight loss at a reasonable rate is the goal. We then arbitrarily designed a 300 calorie diet to be used for children 3 to 8 years, 500 calories from 8 years to puberty, and 700 calories over puberty. This schedule has been effective; hence we have continued it.

This is all to be expected, except that it essentially contradicts items 5 & 6 of Taubes’s “inescapable” conclusions found on page 454. For those that haven’t read GCBC, Taubes attempts to make the case that overeating, exercise, or caloric intake of one’s diet is of no real consequence with regard to weight loss or gain. The only factor that really matters, according to Taubes, is insulin which can be manipulated by dietary carbohydrates.

Of course if Taubes is correct then Sidbury and Schwartz could have prescribed diets of 6000 kcals or more and weight loss would have been just as effective so long as the diet was ketogenic.

* * *

Starting on page 436 Taubes attempts to make the case that carbohydrates cause infertility! So if you’re trying to get pregnant and you’re sitting down to a nice meal of meat and potatoes, put your fork down, discard your potatoes, and help yourself to some more meat.

He starts off by setting up the straw man of Conventional WisdomTM, or in this case Common Belief.

[T]he critical variable in fertility is not body fat, as is commonly believed, but the immediate availability of metabolic fuels.

I’m not even sure why he brings this part up. I guess to add to the list of all the Conventional WisdomTM he has “debunked.” At any rate, as evidence for what is commonly believed he cites a paper by Frisch and MacArthur titled “Menstrual Cycles: Fatness as a Determinant of Minimum Weight for Height Necessary for Their Maintenance or Onset” that concludes the following “The data suggest that a minimum level of stored, easily mobilized energy is necessary for ovulation and menstrual cycles in the human female.”2 The authors also mention that “If a minimum of stored fat is necessary for normal menstrual function, one would expect that women who live on marginal diets would have irregular cycles, and be less fertile, as has been observed, and that poorly nourished lactating women would not resume menstrual cycles as early after parturition as well-nourished women, as also has been observed.” Notice anything funny here? And he contrasts this with two papers by Schneider and Wade that conclude the exact same thing, only they used animals for their studies instead of people.3,4

Whatever. Not a big deal, but strap in because this next one is a whopper. Continuing on pg 436-437 Taubes tries to make the argument that insulin is responsible for infertility, citing some research by Wade and Schneider.

[I]nfusing insulin into animals will shut down their reproductive cycles. In hamsters, insulin infusion “totally blocks” estrous cycles, unless the animals are allowed to increase their normal food intake substantially to compensate.

However, if you actually read the research you will find that it wasn’t the insulin they were studying, but hypoglycemia.4 Insulin was simply a way of artificially inducing hypoglycemia in the hamsters. The authors even mention this:

[I]nsulin was used as a tool to demonstrate the effects of fuel partitioning on reproductive function. Treatments with high doses of insulin that produced hypoglycemia inhibited reproductive function. The results do not support a role for insulin per se, independent of effects on fuel availability.

Emphasis mine. Unless something was really wrong with you, you likely are not going to experience hypoglycemia if you consume a diet that includes at least some carbohydrates. Indeed, those deciding to consume low-carbohydrate diets would be at greater risk of hypoglycemia.5

* * *

If you’re still not convinced that meat = magic then Taubes has a tobacco tale for you on page 437; and a tall tale it is.

Consider nicotine, for instance, which may be the most successful weight-loss drug in history, despite its otherwise narcotic properties.

I wanna stop right here. This is a bold claim. The most successful weight loss drug IN HISTORY? If that’s true then the majority of smokers that I know should be thin. As a matter of fact they should be downright anorexic considering their frequency. Actually, the reverse is true if my experience is any indication. Of course using anecdotal arguments like this is not at all scientific, but c’mon has Taubes never heard of ephedrine? Sibutramine? Dinitrophenol? Amphetamines for god’s sake? Even cocaine?

Absurd historical claim nothwithstanding, he attempts to make the claim that if and when people gain weight after they stop smoking is because smoking is hormonally similar to eating a low-carb diet.

There seems to be nothing smokers can do to avoid this weight gain. The common belief is that ex-smokers gain weight because they eat more once they quit.

[…]

[A]s Judith Rodin, now president of Rockefeller University, reported in I987, smokers who quit and then gain weight apparently consume no more calories than those who quit and do not gain weight. (They do eat “significantly more carbohydrates,” however, Rodin reported, and particularly more sugar.) Smokers also tend to be less active and exercise less than nonsmokers, so differences in physical activity also fail to explain the weight gain associated with quitting.

There’s the ol’ Common BeliefTM again. I guess he figures he wore out Conventional Wisdom so he’ll go with another phrase that means the same thing. Nevertheless, reading this passage Taubes would have you believe that people lose weight after they quit smoking and weight gain in these instances is completely divorced from the amount of calories they eat. As evidence he cites a paper by Judith Rodin, but perhaps more importantly he does NOT mention contradicting evidence from other papers that he cited on the very same page! Por ejemplo, when discussing other aspects of nicotine he cites a review paper titled “Smoking Cessation and Weight Gain” published in 2004, which states

Mechanisms of weight gain [following smoking cessation] include increased energy intake, decreased resting metabolic rate, decreased physical activity and increased lipoprotein lipase activity (14–16,20–23). Nicotine significantly decreased body weight and food intake via a decrease in meal size and a longer inter-meal interval […]6

Another review titled “Weight Gain Following Smoking Cessation” that Taubes cites on this very page relates the following:

Nicotine has commonly been called an anorectic, an agent that suppresses eating. Consistent with this view, the vast majority of prospective studies have found a sharp increase in eating during the first few weeks of smoking cessation (e.g., Hatsukami, Hughes, Pickens, & Svikis, 1984; Perkins, Epstein, & Pastor, 1990; Spring, Wurtman, Gleason, Wurtman, & Kessler, 1991). The magnitude of this increase (approximately 250-300 kcals/day) is strikingly similar across studies, despite important differences in food measurement methodology (e.g., observation of food intake in in-patients, subject self-report by means of food diaries) and subject populations (female subjects, male subjects, or both).7

But Taubes dismisses all of this evidence by glossing over it and highlighting the single Rodin publication, which looks at current smokers and those that recently quit.8 If you actually read the text of the study you’ll find that the quitters on average did not gain significantly more weight than the smokers. Moreover, almost half actually lost weight after quitting. It is also worth noting that the measurement of caloric intake was self-reported, and self-reporting energy intake has been shown to be notoriously unreliable. But I’m sure this singular study with self-reported intake and non-significant results trumps all the other evidence to the contrary.

* * *

On page 446 Taubes says the following:

Avoiding carbohydrates will lower insulin levels even in the obese […]

Now this is a pretty anodyne and uncontroversial statement. I doubt you’ll find any nutrition professional worth their salt that would disagree with the above statement. What is interesting about this is not the statement, but the source Taubes cites for this. It absolutely backs up that claim, but it is devastating to his other claims. Namely, #6 and #9 of his “inescapable” conclusions found in the epilogue.*

The cited study take obese individuals and feeds them isocaloric high and low carb diets as well as hypocaloric high and low carb diets.9 All participants on the isocaloric diets10 maintained their weight whether fed high or low carb diets. All participants fed the hypocaloric diets lost weight regardless of the relative amount of CHO was in the diet. This is actually a pretty damn good experiment to test Taubes’s main hypothesis of calories vs carbs, and the good old calorie wins.

high low carb insulin

* * *

Not a major point but on page 446 Taubes says

It also makes us question the admonitions that carbohydrate restriction cannot “generally be used safely,” as Theodore Van Itallie wrote in 1979, because it has “potential side effects,” including “weakness, apathy, fatigue, nausea, vomiting, dehydration, postural hypotension, and occasional exacerbation of preexisting gout.”

It’s basically a misquotation on two accounts. Van Itallie actually states that low calorie diets “can generally be used safely.”11 Secondly, he states that low calorie diets that are ALSO low in carbohydrates have potential side effects. He is not speaking of carbohydrate restriction in general terms as Taubes implies.

* * *

Page 447, Taubes contends that, although cholesterol levels may rise on a low-CHO diet, it is by no means permanent.

The existing evidence suggests that this effect will vanish with successful weight loss, regardless of the saturated-fat content of the diet. Nonetheless, it’s often cited as another reason to avoid carbohydrate-restricted diets and to withdraw a patient immediately from the diet should such a thing be observed, under the mistaken impression that this is a chronic effect of a relatively fat-rich diet.

Maybe this is another minor point, but the “often cited” part of his claim is in reality a single newspaper article about a guy that sues the Atkins estate for his high cholesterol.12 The article seems to imply that the case is kind absurd and that a judge would almost certainly throw out the suit.

 

 

*For those that don’t have the book…
“6. Consuming excess calories does not cause us to grow fatter, any more than it causes a child to grow taller. Expending more energy than we consume does not lead to long-term weight loss; it leads to hunger.”
“9. By stimulating insulin secretion, carbohydrates make us fat and ultimately cause obesity. The fewer carbohydrates we consume, the leaner we will be.”

cloudReferences

1. in Childhood Obesity (ed. Collip, P. J.) (Distributed by Medical and Technical Publishing Co, 1975).

2. Frisch, R. E. & McArthur, J. W. Menstrual cycles: fatness as a determinant of minimum weight for height necessary for their maintenance or onset. Science 185, 949–951 (1974).

3. Schneider, J. E. & Wade, G. N. Availability of metabolic fuels controls estrous cyclicity of Syrian hamsters. Science 244, 1326–1328 (1989).

4. Wade, G. N. & Schneider, J. E. Metabolic fuels and reproduction in female mammals. Neurosci. Biobehav. Rev. 16, 235–272 (1992).

5. Colle, E. & Ulstrom, R. A. Ketotic hypoglycemia. J. Pediatr. 64, 632–651 (1964).

6. Filozof, C., Fernández Pinilla, M. C. & Fernández-Cruz, A. Smoking cessation and weight gain. Obes. Rev. 5, 95–103 (2004).

7. Perkins, K. A. Weight gain following smoking cessation. J. Consult. Clin. Psychol. 61, 768–777 (1993).

8. Rodin, J. Weight change following smoking cessation: The role of food intake and exercise. Addict. Behav. 12, 303–317 (1987).

9. Grey, N. & Kipnis, D. M. Effect of Diet Composition on the Hyperinsulinemia of Obesity. N. Engl. J. Med. 285, 827–831 (1971).

10. (except for one that did not consume all of the prescribed diet).

11. Bray, G. A. Obesity in America: a conference. (U.S. Dept. of Health, Education, and Welfare, Public Health Service, National Institutes of Health, 1979).

12. Burros, M. Dieter Sues Atkins Estate and Company. New York Times 1 (2004).

Good Calories, Bad Calories: A Critical Review; Chapter 8 – The Science of the Carbohydrate Hypothesis

coverIntroduction

This is another post in my ongoing series of posts on Gary Taubes’s Good Calories, Bad Calories (GCBC). Several of the publications that Taubes cites for various claims are amazingly obscure. I’m working on getting a couple of them right now, so perhaps this post will be updated in the future when I receive and look through them. In the meantime this post is the fact-checking I have done of chapter eight so far.

Surprisingly it doesn’t contain that much “science of the carbohydrate hypothesis.” It’s really more of an introduction to the similarly-named chapters toward the end of the book. He spends some time with Tokelau (which I will get to soon), discusses what homeostasis is, and then reworks one of his earlier articles about salt toward the end of the chapter.

Not the Introduction

God, I love the beach. I bet it's paradise over there.

Ian Prior in Tokelau, 1971

For the first several pages of chapter eight Taubes discusses a rather interesting cohort study involving the people of the Tokelau Islands in the south pacific. Briefly, Ian Prior, an epidemiologist from New Zealand, decided to study the residents of Tokelau while the New Zealand government wanted to organize a large voluntary migration effort of the peoples from the islands to NZ. Some opted to stay on the Tokelau Islands rather than migrate, which provided Prior an excellent opportunity to study the two populations and compare their lifestyles, diet, and health. As you might guess, the islanders that “immigrated” to NZ ended up having more health problems than those that stayed behind.

Why? What happened? According to the University of Minnesota synopsis of the study, it is due to “the tendency for migrants at all ages to be heavier than non-migrants. Migrants had more diabetes and smoked more, drank more alcohol, and exercised less.1 These factors make the poorer health among the migrants pretty easy to explain. Taubes, however, doesn’t want you to think that any of this has to do with the study results so he straight-up lies to you on page 138:

A number of factors combined to make this higher disease incidence among the migrants difficult to explain. For one thing, the Tokelauans who emigrated smoked fewer cigarettes than those who remained on the atolls, so tobacco was unlikely to explain this pattern of disease.

He goes on to state that the migrants were far more physically active and had a much more “rigorous” lifestyle than the non-migrants because they worked in sewing factories and had to walk to shops. I’m not even kidding. Again, this directly contradicts the actual study results.

So how does Taubes explain the health discrepancy? Why, it’s exclusively due to saturated fat intake, of course! Yes, as it turns out the native diet of the Tokelauans ate a diet largely composed of fish, coconuts, and fruit. According to Taubes it was the coconut oil in the Tokelauan diet that was apparently uniquely protective because coconut oil has saturated fats. Moreover, Taubes also mentions that the migrants to NZ started eating bread and potatoes which contributed to their health problems. And, of course, he has to drag Keys into this saying “If Keys’s hypothesis was correct, the migrants should have manifested less evidence of heart disease, not more.”

Actually, no. The non-migrants should have manifested less heart disease. Taubes is conflating the fatty acids in coconuts with all saturated fatty acids. The fatty acids in coconuts are quite a bit different from that fatty acids found in the foods that Taubes promotes throughout the book (beef tallow, bacon, cheese, etc.) It has been demonstrated to the satisfaction of most people that coconut oil does not have a huge impact on serum cholesterol levels and by extension heart disease. Matter of fact, the first person to demonstrate this was none other than Ancel “Beelzebub” Keys himself!2,3

Aside from alcohol consumption, diet was not even mentioned in the study synopsis as being a potential factor in the health decline. Nevertheless, Taubes credits the saturated coconut oil for the good health of the non-migrants, and blames the bread and potatoes on the poor health of the migrants. What Taubes glosses over are other dietary components introduced to the migrants which include salt, eggs, dairy, and red meats.4

* * *

One of the main goals of GCBC is to upend everything we all thought we knew about nutrition: Saturated fats from animals are actually good for you! Carbohydrates from fruits, vegetables, or grains are actually the enemy! Calories don’t matter! You can gorge yourself of whatever you like, and as long as it doesn’t include carbohydrates you’re in the clear! Dietary fiber is meaningless! I suspect Taubes does this not because these things are true or even that he believes these things are true, but rather because it sells more books. It’s a shame people have to get wildly inaccurate information about how to take charge of their own health for the financial gain of one individual, but that seems to be the case.

Another one of these bits of “conventional wisdom” that he upends is the idea that salt has anything to do with high blood pressure. Page 146:

[P]ublic-health authorities for the past thirty years have insisted that salt is the dietary cause of hypertension and the increase in blood pressure that accompanies aging. […] That’s the hypothesis. But in fact it has always been remarkably difficult to generate any reasonably unambiguous evidence that it’s correct.

He goes on to state that even if by some miracle salt really does somehow influence blood pressure, it has such a negligible effect that cutting salt intake “makes little difference” to our overall health. As evidence he cites a 2004 Cochrane Review by He and MacGregor. Old versions of Cochrane reviews are difficult to find. It seems they usually replace the old ones every time the data gets updated. In this case I was only able to find the 2013 version of the same title by He and MacGregor.5 Let me quote from the end of the review (emphasis mine):

Our meta-analysis of randomised trials of longer-term modest reductions in salt intake demonstrates a significant effect on blood pressure in individuals with both elevated and normal blood pressure. The blood pressure fell, on average, by 5/3 mmHg in hypertensives and 2/1 mmHg in normotensives. These falls in blood pressure would have an immediate and significant impact on population blood pressure and would, therefore, be predicted to reduce stroke deaths by approximately 14% and ischaemic heart disease (IHD) deaths by 9% in individuals with elevated blood pressure, and in individuals with normal blood pressure reduce stroke and IHD deaths by approximately 6% and 4% respectively. It is important to note that these reductions in stroke and IHD deaths were estimated from a previous meta-analysis of prospective observational studies. A recent meta-analysis of 1 million adults in 61 prospective studies demonstrates that the relationship between blood pressure and cardiovascular risk is much stronger than previously estimated. Therefore, the reductions in stroke and IHD with the modest reductions in salt intake might be even greater. Since raised blood pressure is also a major risk factor for heart failure, a reduction in salt intake would likely reduce the incidence of heart failure.

I’ll leave it up to you if you think if a modest reduction in salt intake in fact “makes little difference.”6

* * *

Taubes tries to make the case that CHOs are the real culprit leading to insulin resistance which leads to hypertension and ultimately atheroslcerosis. Page 150 of the hardback Taubes states:

Finally, by the mid-1990s, diabetes textbooks, such as Joslin’s Diabetes Mellitus, contemplated the likelihood that chronically elevated levels of insulin were “the major pathogenetic defect initiating the hypertensive process” in patients with Type 2 diabetes. But such speculations rarely extended to the potential implications for the nondiabetic public.

Taubes is quoting out of context here. The actual quote states7:

Should hyperinsulinemia be the major pathogenetic defect in initiating the hypertensive process in patients with NIDDM, it is unlikely that it sustains the hypertension indefinitely. With increasing insulin resistance, the pancreas must secrete higher levels of insulin. Eventually, its reserve capacity is exhausted and plasma insulin levels fall. Other mechanisms must then sustain the hypertension.

Interestingly, immediately before the cherry-picked quote from Taubes is a statement that contradicts Taubes’s argument:

[H]ypertension and insulin resistance may be different clinical manifestations of a common underlying cellular defect by which the level of cytosolic free calcium is increased and the level of intracellular free magnesium is decreased.

As a matter of fact the entire paper makes the argument that the cause of hypertension is clearly multifactorial.

* * *

Page 150:

Though this carbohydrate-induced water retention and the hypertensive effect of insulin were occasionally discussed in nutrition and dietetics textbooks-Modem Nutrition in Health and Disease, for example, which was published in 1951 and was in its fifth edition by the 1970s-they would appear solely in the technical context of water and electrolyte balance (sodium is an electrolyte), whereas the discussion of hypertension prevention would focus exclusively on the salt hypothesis.

Nope. Not even close. Modern Nutrition in Health and Disease describes a variety of factors associated with hypertension. And when it comes to prevention does not “focus exclusively on the salt hypothesis.” Example from the 1999 edition that I have:

In hypertensives whose blood pressures have been controlled with medications, weight loss or NaCl restriction more than doubles the likelihood of maintaining normal blood pressure after withdrawal of drug therapy. The following lifestyle modifications have been recommended as adjunctive or definitive therapy for hypertension: weight reduction if overweight; aerobic exercise; limited NaCl and alcohol intake; maintenance of adequate dietary potassium, calcium, and magnesium intake; smoking cessation and reduced dietary saturated fat and cholesterol intake for overall cardiovascular health.

It’s a shame Taubes never reads what he cites.

cloud

Refs