Preventive Medicine: Keto, balance, and the weight of the world

Dr. David Katz

A colleague asked me if I thought a recent article in the New York Times on the health effects of the ketogenic diet by Anahad O’Connor was balanced. In a superficial sense, the answer might have been “yes.” O’Connor considered pros and cons, noted opposing views by relevant experts, cited some salient concerns, and acknowledged the absence of much relevant evidence — notably, longer term effects.

But my answer was “no,” and it had nothing to do with how O’Connor treated the material he did cover. It had everything to do with what he left out altogether.

Before I tell you what that was, let’s examine an analogy. Not all that many years ago, textbooks on infectious diseases would have been entirely silent on the topic of peptic ulcer disease. When I began my medical training in the 1980s, everyone (more or less) still thought gastric ulcers resulted exclusively from over-production of stomach acid, related in part to diet, and in particular, stress. Medications such as aspirin and anti-inflammatories were known to inflame the stomach and increase susceptibility.

There was no awareness of an infectious etiology until the discovery in 1982 of the bacterium now called Helicobacter pylori, which led to a Nobel Prize in Medicine in 2005. Now, of course, all major textbooks on infectious disease address peptic ulcer, often with a chapter all its own (chapter 218 in this case). A modern textbook on infectious disease would be deficient, and we might say “unbalanced,” were it to omit this topic.

So, too, for the environmental impact of dietary choices. Environmental degradation is the single greatest human health threat of our age, the Anthropocene.

The idea that environmental effects are health effects was novel at the start, just like the idea that peptic ulcers might be an infectious disease. Now, the former, just like the latter, is established fact.

Diet, of course, is not the cause of our stark, dire environmental woes — but it is an important cause. What we eat at the scale of nearly 8 billion hungry Homo sapiens, and how we produce that food, has massive implications for greenhouse gas emissions, water utilization, soil viability, air quality, biodiversity, and more.

The ice in Iceland is melting, and diet is an important reason why. Island nations are sinking, and diet is an important reason why. The Amazon is ablaze, as has been the rain forest in Borneo, and diet is an important reason why. The permafrost is disappearing, and diet is an important reason why. We are ever more prone to floods and fires and droughts, and diet is part of the explanation. This planet’s greatest native treasure, its stunning biodiversity, is desperately imperiled — and in part because we are eating it to death.

All of these, and myriad other environmental degradations, translate very directly into adverse human health effects. Ecosystem disruptions are responsible for emerging infections, from anaplasmosis to Zika. The profound influence of social determinants of health is epidemiologic gospel, and these determinants are devastated among the increasing ranks of climate refugees. Declining air quality means increasing rates of respiratory disease. Fires, floods, tornadoes, and hurricanes are lethal in the most obvious of ways.

Diet, and most particularly meat production and consumption, is a key contributor to the causal pathways involved.

Planetary health effects are human health effects, and ostensibly the most profound of all. For the health effects of keto, or any diet, to be weighed and measured adequately at this juncture in history, it is not enough to consider only the temporary fluctuations in the weight of people, and the attendant flux in biomarkers. The literal weight of the world, its glaciers and aquifers; sea levels and soil quality; average temperatures and food production; its rain forests and permafrost; its biodiversity and extinction rate, must be placed on the scales. Nowhere in all the vast medical literature is there a single example of health in a species without a viable planet to call its own.

So, no, the coverage of keto was not balanced. What could be more unbalanced than sleepwalking off a cliff? The blunt reality of the landing is the gravest health effect of all.

Dr. David L. Katz, is author of “The Truth about Food“; president of the True Health Initiative

Connecticut Media Group