At least get the facts right…

Dr. David L. Katz has no patience for “New-Age nutrition” and its apparent assault on the calorie. See, for example, last October’s The Race to Redefine Calories: Iconoclasts, Start Your Engines! and his more recent Newtonian Nutrition. Unfortunately, while taking people to task for getting the science and facts wrong, Katz gets a rather basic fact wrong, a fact that stands at the center of both his posts.

Katz and his fellow scientists should expend as much energy confirming facts and evidence outside their fields of expertise as they expend policing the facts and evidence within their domains of expertise (or they could consult with experts in those fields or stop thinking their scientific expertise gave them license to speak about any topic).

New-Age nutrition has, it seems, mounted a two-pronged attack on the calorie, one the one hand, denying the basic definition of the calorie and, on the other, doubting whether or not all calories count (at least count the same). Katz’s position seems to be: while there are junk calories and high-quality calories, in the end a calorie is a calorie is a calorie. When it comes to weight (and obesity), what matters, quite simply, is the number of calories. As he says in his earlier post, The Race to Redefine Calories:

The evidence that the quantity of calories counts, along with the quality, is incontrovertible-beginning with the laws of thermodynamics first established by Sir Isaac Newton. There is a fixed relationship between matter and energy, bound by the laws of physics. Biological variation is important, but physics is the bedrock on which other sciences, including biology, must stand.

Katz rephrases this point in his more recent Newtonian Nutrition:[1]

The Huffington Post added this nice image of Newton to its version of Katz’s post.
The Huffington Post added this nice image of Newton to its version of Katz’s post.

Newton’s First Law of Thermodynamics asserts, essentially, that energy can neither be created nor destroyed in any closed system—it has to go from somewhere, to somewhere else. Energy and matter can be interconverted—as is the case when the energy represented by calories is converted to the smaller (glycogen) or the larger (fat) of the body’s energy reserve depots.

In other words, according to the “laws of thermodynamics first established by Sir Isaac Newton,” or more precisely, “Newton’s First Law of Thermodynamics,” unused calories become mass.

Okay, except Isaac Newton had nothing to do with the laws of thermodynamics. Newton died in 1727. The laws of thermodynamics were worked out over a century later, in the mid-19th century. Katz’s argument contains a serious factual error.

While Katz’s error has nothing to do with the First Law of Thermodynamics, per se, his mistake weakens his position. First, it undermines his argument in The Race to Redefine Calories where, in the end, he resorted to an argument from authority, saying:

The race to redefine the calorie has a vociferous group of iconoclasts revving their engines. If you are genuinely convinced that any of these characters is smarter than Sir Isaac Newton, and/or has probed to levels of understanding beneath the bedrock of physics, by all means, wave the checkered flag.

If you are going to present an argument from authority, you should at least get your authority correct.[2] Second and more broadly, Katz’s blunder—and that’s what it is, a blunder—detracts from his point by calling into question his general commitment to facts and evidence. It was not a “short-cut,” as he asserted in a tweet.[3]

David Katz dismisses his error as a “short-cut” (link).
David Katz dismisses his error as a “short-cut” (link).

It was and, since he hasn’t corrected his post, remains a mistake that suggests a casual disregard for facts. Or maybe he doesn’t think all facts are the same. Maybe some facts count more than others. Scientific facts—a calorie, for example—are a high-quality facts while historical facts are junk facts. Maybe this is some form of pop culture, New-Age history that questions the basic merit of “the fact.” Unfortunately, there is something of a cottage industry in this particular brand of history.[4] Katz is not alone in his gratuitous and careless use of historical facts. But just like his scientific colleagues, Katz didn’t need to invoke history, didn’t need to appeal to Newton in his criticism of “New-Age nutrition.” Once he did, however, he still has a scholarly and methodological (and an ethical and moral) obligation to get the scientific and historical facts correct.

Katz should care about getting all the facts correct. Anything less subverts his argument and squanders an opportunity for real change.


  1. The Huffington Post reposted Katz’s post unchanged and unchecked, complete with the egregious error: “Newtonian Nutrition” (I cannot bring myself to link to this version of Katz’s post). It is unfortunate that a media outlet as influential as the Huffington Post disseminates misinformation like this. The Huffington Post complete lack of editorial oversight and intervention in so much of the material it reposts is good reason to avoid it.  ↩

  2. Scientists are rightly suspicious of and condemn such arguments in their professional writing and in the writing of their opponents. This unvarnished argument from authority is, consequently, all the more jarring. Katz also flirts with an argument from authority in his more recent post, where he says: “Arguments against the fundamental utility of the calorie to human energy balance, and weight control, really do devolve to arguments against Newton and this basic law.” Goodness knows we are not as smart as Newton, who was, after all, a genius. If he said it was so, it must be so. Oh wait, he didn’t say it was so.  ↩

  3. There is an odd attempt to dodge responsibility in Katz’s tweet: “FL of T appears to have passed through many hands. to whom do you attribute?” Katz seems to try to dismiss his error as understandable and forgivable because the history is complicated. He’s right: history is complicated and difficult. Historians spend years developing the skills and expertise to do history. But this is not a question of interpretation or source criticism or esoteric knowledge. This is a factual question that can be resolved pretty easily: what we call the First Law of Thermodynamics was developed more than 100 years after Newton died. The laws of physics make it impossible for the First Law of Thermodynamics to have “passed through” Newton’s hands. [There is another problem in his tweet: Katz seems to be searching for the father of the First Law of Thermodynamics (on the problems with the search for the “father of” something, see Thony C’s many posts, e.g., this one or this one).]  ↩

  4. These last two sentences paraphrase and repurpose the first two sentences of Katz’s “Newtonian Nutrition” post—see the screen shot from the Huffington Post above.  ↩