Good Calories, Bad Calories: A Critical Review; Chapter 12 – Sugar

Introduction

This post is another in a long line of self-abusive posts in which I spend way too much time combing Gary Taubes’s Good Calories, Bad Calories (GCBC), and usually end up disappointed at the publishing industry and feel depressed for the masses of people that actually trusted Taubes’s “research.”

This chapter is not as bad as many of the others, though. It happens to be about sugar, and the fact is that you don’t need to heavily distort scientific publications to indict sugar. Taubes still manages it, however. If you’d like to read other chapter reviews of GCBC by yours truly, visit my Book Reviews page.

As you read this post you might leave with the impression that I advocate sugar consumption. Nothing could be further from the truth: it is clearly an ingredient that Americans (and perhaps any country with a Pepsi presence) consume far too much. It would only benefit your health to reduce your consumption of it. What I do advocate is intellectual honesty which is why I come to sugar’s defense when journalists like Taubes make up or distort evidence against it.

Not the Introduction

On page 200 Taubes states 

The more fructose in the diet, the higher the subsequent triglyceride levels in the blood. For this reason, fructose is referred to as the most lipogenic carbohydrate.*

*Credit for this observation dates to 1916, to Harold Higgins of the Nutrition Laboratory of the Carnegie Institution.

I’m not sure that Taubes can really state this. The Higgins paper he cites does not really measure lipogenesis. It measures respiratory quotient. In the paper Higgins does say that one might say that levulose (fructose) and galactose, judging by the RQ, could preferentially turn into fat.1 However, Higgins actually observed the sugars being burned:

A study of figure 1 shows clearly that levulose [fructose], sucrose, probably lactose and possibly maltose give indications by the respiratory quotients of being metabolized, and in all probability burned by the fourth to the seventh minute after ingestion “on an empty stomach,” which is quite as rapidly as alcohol in the same subject and much quicker than alcohol in four other subjects.

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On page 200, Taubes states

Although sugar also seemed to raise cholesterol levels, particularly LDL, as would be expected for any nutrient that increased triglyceride synthesis in the liver. In 1992, John Bantle reported that LDL cholesterol in diabetic patients was elevated more than 10 percent on a high-fructose diet after a month, which is comparable to what can be achieved by saturated fats.

For this claim he cites two references. One is a study co-authored by Bantle (although he is not the lead author, Joyce Swanson is).2 That study does show that at a couple of points in the study LDL was elevated compared to the controls, as was triglycerides at one point and total cholesterol at one point. (See pic below) However, contrary to Taubes’s claim this study used normal, healthy patients – not diabetics.

Metabolic effects of dietary fructose in healthy subjects

Dietary fructose effects on lipoprotein metabolism and risk for coronary artery disease

The other citation for his claim that fructose elevates LDL is a review article that makes more of a point to state that the evidence on this issue is quite conflicting.3 (see pic above) From the author’s conclusion:

Perhaps the most general conclusion that could be drawn from this review of the effects of dietary fructose on lipoprotein metabolism is how little we actually know.

Does Taubes even read the studies he cites? And shockingly Taubes now admits that sat fat can raise LDL cholesterol levels!

Also from the conclusion:

[I]t would seem unlikely, based on available data, that dietary fructose at quantities obtainable from natural sources provided in a well-balanced diet would result in any deleterious metabolic effects.

* * *

On page 201 Taubes claims:

[F]ructose elevates blood pressure more than an equivalent amount of glucose does, a phenomenon called fructose-induced hypertension.

What you might think after reading this statement is that if you consume fructose this might lead to some degree of hypertension, but unless you’re a rat you would be wrong. Taubes cites two publications for this claim: one by Hodges and Rebello and one by Hwang et al.4,5 Both mention that fructose consumption leads to hypertension in rats. In fact the title of the Hwang paper is “Fructose-Induced Insulin Resistance and Hypertension in Rats.” However, you will find the opposite is true in humans. The other paper makes it clear that fructose has no effect on blood pressure in humans. From the text: “Fructose ingestion produced no significant changes in blood pressure […]” The authors also mention that lactose and galactose also showed no increase in blood pressure. Although to be fair to Taubes the study does mention that both sucrose and glucose increased blood pressure in humans so he’s not way off base here. Nevertheless, he seems to give all the studies he cites a mere cursory glance before writing about their results and very often getting them wrong.

* * *

Page 202, Taubes claims: “The American Journal of Clinical Nutrition dedicated an entire issue to the deleterious effects of dietary fructose.” Not exactly true. The AJCN did do a supplement of one issue that focused on fructose, and it wasn’t focused on the deleterious effects, either. Some of the reports had nothing to do with fructose and health. Just look at some titles like “Manufacturing, composition, and applications of fructose” and “Worldwide production of high-fructose syrup and crystalline fructose.” Other reports indicated neutral to favorable data regarding fructose and health. For example, one report on diabetes concluded6:

In summary, the side effects of fructose supplementation do not seem at this time to be of particular concern when fructose is ingested in modest amounts.

Another report on the public health implication of fructose states7:

On the basis of currently available information, as reviewed in this monograph, fructose is a valuable, traditional source of food energy, and there is no basis for recommending increases or decreases in its use in the general food supply on in special dietary use products.

Another report says that fructose aids in mineral absorption.8 Another says that fructose may increase physical performance.9 These are all from the same supplement that Taubes mentions. I know this because Taubes even cites yet another report on fructose and thermogenesis that concludes the following10:

The greater thermic effect of fructose, its nondependence on insulin for its metabolism, and its greater sweetening potency compared with glucose are factors that may speak in favor of fructose as a valuable carbohydrate for the dietary management of obesity and NIDDM [non insulin-dependent diabetes mellitus].

But of course there was no way in hell Taubes was going to mention this part of the conclusion. Instead he mentions the part that says more research is needed – a sentiment you can find at the end of literally all nutrition studies and likely any scientific study period.

* * *

Page 203:

In 2002, the Institute of Medicine of the National Academies of Science released its two-volume report on Dietary Reference Intakes (subtitled Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids), and spent twenty pages discussing the possible adverse effects of sucrose and high-fructose corn syrup. It then concluded that there was still “insufficient evidence” to set up an upper limit for sugar consumption in the healthy diet.

Despite Taubes’s attempt to make this seem like a huge scandal because of a wildly incompetent Institute of Medicine, this is pretty standard stuff. No tolerable upper limits (UL) were set for any macronutrient. ULs are set for things like vitamin A and iron; micronutrients at which there is a point where they start to become acutely toxic.

Refs

1. Higgins, H. L. The Rapidity with Which Alcohol and Some Sugars May Serve as Nutriment. Am. J. Physiol. 41, 258–265 (1916).

2. Swanson, J. E., Laine, D. C., Thomas, W. & Bantle, J. P. Metabolic effects of dietary fructose in healthy subjects. Am. J. Clin. Nutr. 55, 851–856 (1992).

3. Hollenbeck, C. B. Dietary fructose effects on lipoprotein metabolism and risk for coronary artery disease. Am. J. Clin. Nutr. 58, 800S–809S (1993).

4. Hodges, R. E. & Rebello, T. Carbohydrates and blood pressure. Ann. Intern. Med. 98, 838–841 (1983).

5. Hwang, I. S., Ho, H., Hoffman, B. B. & Reaven, G. M. Fructose-induced insulin resistance and hypertension in rats. Hypertension 10, 512–516 (1987).

6. Gerrits, P. M. & Tsalikian, E. Diabetes and fructose metabolism. Am. J. Clin. Nutr. 58, 796S–799S (1993).

7. Glinsmann, W. H. & Bowman, B. A. The public health significance of dietary fructose. Am. J. Clin. Nutr. 58, 820S–823S (1993).

8. O’Dell, B. L. Fructose and mineral metabolism. Am. J. Clin. Nutr. 58, 771S–778S (1993).

9. Craig, B. W. The influence of fructose feeding on physical performance. Am. J. Clin. Nutr. 58, 815S–819S (1993).

10. Tappy, L. & Jéquier, E. Fructose and dietary thermogenesis. Am. J. Clin. Nutr. 58, 766S–770S (1993).

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