I met Mo Perry last year when she interviewed me for an article. She followed up with a wonderful article for Sensible Medicine in 2025 titled “The Horseshoe Theory of Alternative and Conventional Care.” I respect her ability to consider complicated issues in clear and thoughtful ways.
This essay is on the long side for us, but I think it warrants space, and not just because I am part of its subject. It tackles the question, “What is medicine for?” by considering what conventional and functional/integrative medicine offer. Like the best essays, I left if more confused than I was when I started it.
Adam Cifu
When I was about eight, I saw a magic trick at a birthday party. The magician raised a pitcher in one hand and a bowl in the other, then poured a stream of sparkling blue water from the pitcher into the bowl. But when he showed us the inside of the bowl, it was empty.
I’ve cycled through various theories for how this worked, but I’ll likely never know for sure.
It’s a little like the body: Something happens. We can see that it happened. But often, why and how remain a mystery.
I’ve spent much of my career probing such mysteries as a freelance magazine writer, covering health topics largely through a functional/integrative-medicine lens. I’ve written about everything from hormones to autoimmunity to complex digestive disorders. As I have zero medical training, these articles rely heavily on expert input, largely from functional, integrative, and sometimes naturopathic doctors who I find insightful and trustworthy.
I’m proud of the work I’ve done. But new doubts are starting to haunt me. I’ve been an enthusiastic reader of Sensible Medicine since it launched in 2022, and its rigorous examinations of medical evidence have led me to cast a newly wary eye on the functional/integrative world’s confident mechanistic stories, often built on shaky evidentiary ground.
Much of what the functional world asserts — that prevention can avert the need for later treatment; that diet and lifestyle are potent tools for health and healing — seems intuitively true. But if there’s one thing I’ve learned from reading Sensible Medicine, it’s that medical claims that feel intuitive often prove to be false. Is it true that cutting out gluten can preserve or restore thyroid function in people with Hashimoto’s? Is there real evidence that healing a leaky gut with an elimination diet and gut-repair supplements resolves inflammatory symptoms?
Doctors I’ve interviewed insist they’ve seen exactly these outcomes in their practices. But every kid at that birthday party would’ve sworn that they’d watched a pitcher’s worth of water vanish into thin air. Is it possible these doctors are equally certain of what they’ve seen, and just as wrong about why?
Then again, if their patients really did achieve better function, less pain, or fewer symptoms, does it really matter if the explanatory model isn’t exactly true? Isn’t that largely the story of health and healing throughout human history, even in the supposedly evidence-based medical world? (How many people who recovered from the flu after a dose of Tamiflu believed the pill was pivotal? Ditto Paxlovid for Covid, or surgery for meniscal tears.)
Dr. Wayne Jonas writes in his terrific book How Healing Works,
Researchers at the Society for Interdisciplinary Placebo Studies have shown that three [things] — belief and expectation, meaningful social learning, and reinforcement or conditioning — are the underlying mechanisms of the placebo response, and the likely explanation for the majority of human healing in any system or from any treatment.
Modern medicine has an extraordinary capacity to treat acute illness and save lives. But much of health and healing unfolds in a murkier realm, where biology becomes difficult to disentangle from the psyche, spirit, and environment. In this realm, Jonas asserts that good healthcare is mostly about learning how to ethically harness the mechanisms of the placebo response and heal through meaning. I think this is right.
But it does present a tension between epistemic purity and practical results. Prizing either one to the exclusion of the other seems unwise, for both patients and doctors. In the hope of finding a wise middle ground, I sought out a strong advocate for each side.
I spoke with Dr. Adam Cifu, familiar to Sensible Medicine readers as a general internist at the University of Chicago and outspoken champion of evidence-based medicine. I also spoke with Dr. Rahul Iyengar, a family physician and founder of a concierge primary care clinic in Nashville focused on prevention and health optimization.
Despite their philosophical differences, Cifu and Iyengar agree on quite a lot. Both think time, attention, and careful listening are central to good healthcare — and that the current system makes those things difficult.
“Conventional medicine has sort of invited the rise of alternative medicine because we do such a crappy job at [using] the placebo effect,” Cifu told me. “We’ve outsourced it, saying, ‘I don’t have a pill for this, so go find somebody who will convince you they’re doing something.’” He’d like to see primary care generalists have more time to provide caring attention, which he sees as the main thing that helps when there’s no obvious medical fix. For his part, Iyengar founded his clinic specifically out of a desire to have the time to provide “relationship-based care.”
They also agree that diet, exercise, and basic lifestyle factors matter more than elaborate optimization regimens. And neither has much patience for the wilder reaches of the wellness marketplace. “Big Supplement is arguably much scarier than Big Pharma because there’s zero regulation,” Iyengar says. “It’s all just pretty marketing and packaging.”
The differences start to creep in around how much medicine should do in pursuit of health. Specifically, here are four areas where the philosophies meaningfully diverge:
1. When should medicine intervene?
The first disagreement is on the value of prevention and optimization.
For Iyengar and many others in the functional/integrative space, waiting for disease to fully manifest before intervening is akin to skipping routine auto maintenance that might prevent a major mechanical problem down the road. “Come see your doctor when you feel healthy,” he says, “and it’s really easy and affordable to keep you healthy as opposed to waiting for something to break.”
He advocates for preventive blood work that goes beyond the standard annual panel, including more extensive cardiac, metabolic, thyroid, and nutritional markers. “Let’s find out all these little things and fine-tune them before you feel bad,” he says. He sees particular value in catching a trajectory early enough that diet or other lifestyle changes may alter it before medication becomes necessary.
Cifu says we need more evidence to know if this juice is worth the squeeze. With LDL cholesterol, for example, we know that lowering very high levels improves outcomes. But once someone is already in the normal range, he says, the absolute risk reduction from pushing it even lower is much smaller. “We don’t know what the benefit of being in that ‘optimal’ realm is. And therefore, people aren’t able to make intelligent decisions about what they’re willing to do to get there,” he says.
This points to a fundamental divide on how readily medicine should expand its attention from disease to health itself. “Doctors do a whole lot more good treating sick people than treating healthy people,” argues Cifu. When medicine makes the jump from treating illness to intervening in healthy people, “that’s where the level of evidence has to be higher, because when you start mucking around with healthy people, you’re just so much more likely to do harm.” That potential harm includes not only side effects and expense, but what he calls the “cognitive risk of ‘I’m unwell. I could be doing things better.’”
Iyengar counters that evidence of prevention’s benefits is hard to produce when trials overwhelmingly study people who are already sick and commercial funding favors interventions with a product at the end. “Who is it going to benefit if the [intervention] is just lifestyle factors or changes? That’s not a product,” Iyengar says. “Who is going to fund the study?”
For now, Cifu doesn’t begrudge anyone their non-evidence-based health pursuits, as long as they’re low-risk and out-of-pocket. “There are people for whom this is a hobby, and it makes them happy to do it,” he says. “I pay money to have access to a ceramics studio. If someone wants to pay money to have access to a functional medicine practitioner doing this stuff, that’s fine. Of course, the benefit of my hobby is that my friends get to receive my pottery.”
2. Is medicine for dysfunction or just disease?
Things get thornier when we move from people who feel healthy to those who don’t. What should medicine offer someone suffering from fatigue, headaches, gut problems, or brain fog when the standard workup comes up empty?
For Cifu, the first obligation is a thorough but bounded diagnostic search – ruling out the common things followed by the less-common possibilities. But at some point, the search has to end. “We can’t clear the differential diagnosis for every problem of every person because it’s impossible.” From there, the doctor’s job is to manage symptoms where possible and stay alert to changes. “The care is attention,” he says. “It’s, ‘I’m still here caring for you.’”
For a patient with vague symptoms and normal bloodwork, Iyengar said he might pursue advanced gut or stool testing, but also a deeper investigation of family and psychosocial history, environmental exposures, occupation, daily habits, even something as mundane as frequent contact with cleaning chemicals.
When I asked Cifu whether conventional medicine sometimes stops looking for the causes of symptoms too soon, he was adamant: “I actually think our problem is the opposite. We so frequently go absolutely crazy in our evaluations. Everything from how we’re trained to where our money comes from incentivizes us to do too much.”
This points to a deeper disagreement about medicine’s purpose: Is it just for diagnosing disease? Or does it extend to identifying modifiable contributors to poor function – to helping people feel better?
For conventional medicine, once a reasonable differential has been exhausted, the responsible answer is often simply, “We don’t know.” Which may be epistemically honorable but doesn’t feel particularly helpful. The integrative model casts a wider net and uses a broader toolkit to pursue better function. This approach has obvious appeal if you’re struggling with mysterious symptoms.
Cifu’s objection is that the more determined you are to find an explanation, the greater the risk that eventually you’ll land on one, one that likely has nothing to do with your symptoms.
3. Where does medicine end?
If some patients may benefit from interventions that fall outside the bounds of evidence-based medicine, should those interventions be brought under the physician’s umbrella, or kept clearly separate?
Cifu is open to patients trying things like acupuncture or naturopathic care when conventional medicine has run out of answers, provided it’s unlikely to cause physical harm, financial harm, or delay necessary care. But he wants a bright line between the two domains.
“It’s a matter of figuring out how to [suggest that as an option] without endorsing it,” he says. “If my office were in a strip mall, I’d want you to have to go out to the parking lot and enter a separate door to see them rather than access both of us from the same waiting room. That would actually be kind of important to me.”
Iyengar’s approach is the opposite. If his patients are going to seek out wellness services anyway, he’d rather bring some of them inside his practice, where they can be offered more safely. His clinic offers massage, IVs, and Botox alongside primary and urgent care; he describes his goal as an all-in-one health ecosystem that blends “prevention, wellness, and health in one spot.” (He draws the line at peptides, which he considers too poorly studied and risky to offer responsibly.)
In my searches for functional-medicine sources, I’ve found an increasing number of them offering “longevity” and aesthetic services. Even functional clinics that don’t offer Botox still often promote services like ozone therapy and nutritional IVs as legitimate health interventions, despite thin evidence.
This is a stubborn pickle. An unbending commitment to the evidence-based toolkit can leave suffering patients at sea with nothing left to try. But if the line between declining something (peptides), offering it (Botox), and promoting it as treatment (nutritional IVs) is up to each individual doctor or clinic’s discretion, this puts a lot of onus on the lay person to select someone whose instincts she can trust, a task most of us don’t have the training or skills to do.
4. Which incentives distort care the most?
Both models contain perverse financial incentives, both obvious and covert. Cash-pay functional medicine can reward practitioners for finding ever more things to test, treat, supplement, and optimize. At the industry’s upper reaches, some of its most prominent figures profit directly from products and services they recommend to their enormous audiences — hardly the personalized, precision medicine they claim to champion.
On the flip side, Iyengar says, “Sick care is truly the biggest industry in America. It incentivizes ongoing treatment, not cures or prevention. And currently, no one’s incentivized to change it.” It’s not that individual doctors want their patients to stay sick, but that the system pays much more readily for treating illness than for the time-intensive work he considers necessary to prevent it (as well as research supporting that work).
All this adds up to a dizzying landscape for the individual patient to navigate, one pulsating with questions of epistemology, money, incentives, blind spots, discernment, and the subtle dimensions of healing that don’t lend themselves to easy quantification.
What’s a health writer to do? What can she confidently assert and advise?
I don’t want to believe or spread a story that’s not true, but I also don’t want to make it my mission to aggressively debunk every act of magic that’s led to real relief from suffering. Like the bowl of disappearing water, healing can be real even when we don’t understand the precise mechanism at play. Maybe the answer begins with being less certain. We can take the healing seriously, even as we hold the explanation for it lightly.
My choice is this: In my life and my writing, I’ll seek out doctors who use evidence as a guardrail while acknowledging its limits; who are open and attuned to the powers of expectation, relationship, and meaning, without confusing them for proof; and who keep a clear line between beauty treatments and medicine. What turns me off, in any direction, is unearned certainty.
Others will make different choices, based on their own calculus. Maybe the wisest thing medicine can do is help us make those choices with our eyes open.
Mo Perry is a national award-winning freelance health journalist and professional stage actor based in the Twin Cities, Minnesota.
Photo by Little Annabell on Unsplash
