I WAS ONE of a handful of disgruntled students at my medical school, each of us with a slightly different axe to grind. Some campaigned for a more sex-positive curriculum; others lobbied at the statehouse on behalf of the uninsured. Some griped about the dubious ethics of summer mission trips abroad; others interrupted pharmacology lectures to ask about the role of yoga and herbs. In my own case, the problems felt more diffuse. I was bored by my science-heavy coursework, but also kind of bad at it. I was jealous of college friends who were pursuing graduate work in the humanities, learning to interrogate institutional structures instead of blindly moving through them. Having retained an adolescent hostility toward hypocrisy and pretense, I was distracted by their ubiquity in the medical setting. Supervising hospitalists would ask for formal patient presentations, for example, then tap their feet impatiently through the protracted social history. Psychiatrists would cycle through various designer antidepressants in an inpatient unit whose bleak furnishings had remained fixed for decades.

The steady rhythm of clinical work, its volume and repetition, wore most of us down eventually. After graduation, we continued our training through residencies and fellowships, winding up as experts in routine patterns of practice. I’m a gastroenterologist now, based at an academic hospital, dividing my time between office visits and endoscopic procedures. An endless stream of urgent referrals saps my energy for interrogating the larger forces shaping my recommendations — pharmaceutical marketing, fee-for-service payment models, medicolegal anxiety. However stifled I might have felt as a student by the gap between medicine’s rhetoric and realities, my professional life has grown, like bonsai, into its constraints.

Of course not everyone adopts such a defeatist posture. Particularly in public-facing medical writing, there’s a tradition of doctors styling themselves as willful cage-rattlers, doggedly opposing whatever they come to see as the field’s cardinal sins. Specific grievances vary from one commentator to the next. Some rebellious physicians, like Mark Hyman and Amy Myers, champion holistic approaches to the body as antidotes to the prevailing paradigm of fragmentary, siloed expertise. Others, like Vinay Prasad and Jennifer Gunter, allege that contemporary health care isn’t scientific enough, its interventional reflexes tainted by cultural biases and skewed commercial incentives.

And some, like Robert Lustig, author of Metabolical: The Lure and the Lies of Processed Food, Nutrition, and Modern Medicine, put forward multiple arguments at once. Lustig, a physician-scientist with a background in pediatric endocrinology, has spent his career thinking about chronic metabolic conditions like diabetes and obesity. In his book, he ascribes their rising prevalence to sinister, systemic influences like processed food manufacturers and agricultural lobbyists, abetted by weak governmental regulation and medical professionals whose grasp of nutritional science falls far short of Lustig’s own.

Like the portmanteau of its title, Metabolical combines multiple existing strains of medical writing. Lustig splices together bits of 19th-century history, carefully diagrammed overviews of cellular biology, and detailed personal accounts of decades-old professional spats. Conjecturing across disciplines, he suggests for instance that processed baby food might have brought beards back into fashion because toddlers were masticating less, leading to a greater likelihood of weaker jawlines in adulthood. He offers a primer on greenhouse gas emissions, pitching processed food as a primary culprit for the climate crisis. But despite his stated interest in institutional dysfunction, his book’s take-home message gets distilled into a strangely inward-looking dietary catchphrase — “protect the liver, heal the gut” — presented as a kind of talisman to protect the individual reader in an age of nutritional conspiracy.

Lustig’s narrative structure has a jumbled quality, with simultaneous critiques of clinical, governmental, and industrial bodies interwoven with chemical structures of fatty acid molecules and references to Jeffrey Sachs and Michael Pollan as personal friends. This haphazard arrangement amplifies the book’s conspiratorial preoccupations, the book reading like a wingnut’s bulletin board. “Doing the research myself,” he explains in his introduction, “was like taking the red pill from The Matrix.” Now, he tells us, he “know[s] just how far down the rabbit hole goes.” The movie reference feels quaint, as if in ignorance of a meme that’s become cultural shorthand for all sorts of fringe movements committed to the exposure of hidden realities. It seems strange for a translational scientist with a vested interest in laboratory data to invoke a symbol so fraught with contemporary political baggage. That said, it does serve to set the stakes of his battle as he sees it, and the heroic role he assigns himself.

Metabolical’s argument is most convincing in its broadest strokes, in the first and last few chapters, which read more like social criticism than self-help. Corporate profiteering undermines the mission of altruism. Treating chronic diseases costs more and helps less than preventing them. The goal of individualized, high-tech biomedicine increasingly diverges from the goal of public health. While these insights aren’t new, the anecdotal evidence that Lustig marshals gives them substance. In describing vanguard stem cell research in diabetes, for example, he contextualizes its life-changing potential as contingent on patients’ ability to afford the treatment. His long-standing scrutiny of nutritional policymaking lets him showcase how special interests have defined many features of the American dietary landscape, from food labels to the National School Lunch Program.

And yet the trappings of the wellness genre prove irresistible. The ninth chapter is titled “Assembling the Clues to Diagnose Yourself,” marking a clear tonal shift from systems-level analysis to personal counseling. Lustig lists in bold four rules for taking charge of a clinical encounter; for example, when discussing vital signs and blood test results with a physician, “Don’t take ‘normal’ for an answer.” Instead, he encourages patients to press for nuance in their diagnostic assessments, uncovering the truth of metabolic dysfunctions that might be elided by overly wide reference ranges. It’s an odd pivot, from blaming the existing biomedical infrastructure for promoting widespread chronic disease to suggesting that personal restitution might come through deeper engagement with that same infrastructure.

For all his emphasis on clinical nuance, his own application of it feels selective — for instance, in reference to certain emergent paradigms in digestive physiology. With all the enthusiasm of a probiotic advertisement, he describes the importance of balance between “good” and “bad” bacteria: “There are two flavors of bacteria in your gut,” he writes, “and it’s a daily struggle to see which will prevail.” In fact, the microbiome is much more complex than this moralized binary suggests, and relatively straightforward questions of bacterial species density and diversity are complicated by variations in their metabolic by-products, amenability to sequencing, and potential interactions with surrounding viruses and fungi. Obviously, one expects a measure of simplification when scientific ideas are presented for lay consumption. That said, one also might expect some self-awareness from a book that repeatedly chides other clinicians for their reductive tendencies.

Books like Metabolical don’t usually receive much critical attention, perhaps for good reason. A line-level unseriousness makes it clear that whatever significance Lustig aspires to, it isn’t literary (“Mo’ pills, mo’ problems,” he quips at one point). My own interest in such books is secondary to the larger question around how doctors give voice to professional dissatisfaction. Health care’s imperfections still strike me as glaring, even as I teleconference with drug reps offering rebate cards and research support, even as I strive toward the annual productivity targets set by my employer. “Modern Medicine is a racket,” Lustig notes early on in Metabolical, a sentiment that rings true to me. And yet his argument takes turns that undermine my sympathy.

Why, for example, does he alloy his broad institutional skepticism with advice on interpreting cholesterol levels? Why does he intersperse his criticism of contemporary medical school curricula with praise for the osteopathic college where he now lectures? Why does he pair his criticism of outmoded nutritional logic with enthusiasm for half-formed models of chronic disease that might, in a few years, be ripe for their own debunking? Is it to fit through the widest available publishing window? Is it to feed the appetite of his presumed readership — an economically advantaged, health-conscious population accustomed to leaving the physician’s visit with an actionable prescription? Or is it difficult for career physicians, even self-proclaimed heretics, to relinquish their impulse to prescribe?

Like other contrarian doctors writing for lay audiences, Lustig foregrounds his professional bona fides to accomplish a particular rhetorical trick: garnering the personal authority necessary to subvert the field from which that authority derives. Most doctors don’t know what they’re doing; take it from me, a doctor. It’s a common strategy among practitioners who straddle the line between orthodox and alternative health care — the rheumatologist who dabbles in acupuncture, the primary care provider who sells crystals in the waiting room. Similarly, Lustig cultivates a professional identity that borrows selectively from the biomedical status quo, holding it at a distance but never really leaving its orbit. He dissociates himself from financial rewards, taking care to note that his specialty is among the lowest paid in medicine, but neglects to quantify the extent to which his salary gets supplemented by speaker’s fees. He rails against conflicts of interest, then offers a favorable review of a food delivery startup without mentioning his role as its chief medical officer. He underscores his long-standing antipathy toward professional societies but mentions his university affiliations dozens of times. More substantively, he agitates at length for substantive change at the population health level while simultaneously exalting his decades-long commitment to a mode of clinical practice that caters to the individual.

This cherry-picking doesn’t matter much, really, except to suggest that despite being packaged as an antiestablishment takedown, Metabolical is most coherent as a professional memoir. It recounts Lustig’s trajectory as a doctor, with special attention to its sore points. Through the book’s messy accumulation of polemic, tutorial, and reminiscence, the strongest common thread is Lustig himself, processing his work in a rear-view mirror. In this sense, Metabolical reminds me of conversations I’ve had since the beginning of my training with older physicians in moments of repose, gray-haired teachers eager to impart their own life lessons — how their practice has changed, how the ground has shifted under their feet, what about it makes them crazy, what they could do better if given the chance.

Not all doctors worry about the higher-order ironies baked into contemporary health care. An easy alternative is to hold to the heroic portrayals of the field that percolated through most of our medical school admissions essays, celebrating clinical work as intrinsically good. There’s great value in counternarratives, but it’s remarkable to me how they can falter in the same basic ways. The heroic register with which purported mavericks like Lustig lay out their particular theories often says less about the impact of their nonconformity than their own regard for it. It also tends to sidestep the basic problem of complicity. Looking backward from his emeritus professorship, the renegade physician lambastes the hubris of his profession, seemingly unbothered by its residue, the traces of hubris that he himself has metabolized.

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Nitin K. Ahuja is an assistant professor in the Division of Gastroenterology and Hepatology at the University of Pennsylvania, where he also serves as co-director of the Program in Neurogastroenterology and Motility.