Tong Yan grew up in a Chinese-American enclave of Los Angeles in a family that revered food, but thought little of those who carried excess weight.

"Definitely there was like an implicit fattist kind of perspective, like small comments that are made about people's weight," Yan says. Obesity did not affect him or his family, but a friend — who wasn't even that heavy — became the butt of jokes. "Also implied was that people who are obese are lazy and not motivated," he recalls.

It wasn't until medical school at George Washington University, that Yan thought deeper about weight stigma, which is widespread in U.S. culture. In year two, he attended an educational summit on obesity put on by one of his professors. As part of the summit, Yan took an implicit bias test that identified his slight bias toward thinner people. Patients also shared personal tales of discrimination faced in exam rooms, and how it affected their health, and their relationship with physicians.

And he learned how factors other than exerting will power to diet and exercise — things like genetics, brain chemistry, stress level, and community design — contribute significantly to the disease.

Now, Yan believes such dedicated training in obesity is essential for doctors-to-be.

"I think it is a start of sort of a reeducation, because whether or not we talk about it, we absorb all the messages about what it means to be called obese, what it means to have a larger body, since the time that we're very small," he says.

And yet obesity training in medicine is still relatively unusual.

"Doctors traditionally learn nothing about obesity, not in medical school or residency," says Dr. Scott Kahan, who teaches at Johns Hopkins and George Washington Universities, and and is the medical director the National Center for Weight and Wellness, a clinic in Washington DC.

"What we learned is essentially just: 'Obesity is very prevalent and you're going to see it in lots of your patients. And it's really important for people to eat less and exercise more'; that's pretty much it," he says.

Obesity affects so many people — 42% of Americans — and is linked to more than 200 other chronic conditions and major causes of death, from heart and kidney disease to diabetes. Its impact on patients and their health care is hard to overstate. And yet, even as scientific understanding of the disease evolves rapidly, doctors are taught very little about the causes of obesity in medical school, and even less about how to counsel or help those who have it.

One 2020 survey found medical schools spend, on average, 10 hours on obesity education. Half of schools say increasing that is a low priority, or not a priority at all.

That's insufficient, given the wide-reaching impact obesity has across the medical profession, says Dr. Robert Kushner, a professor of medicine and medical education at Northwestern University and co-author of the survey.

He says the problem also perpetuates itself: "There aren't a lot of people trained in obesity," he says, and "if you weren't trained in medical school and you didn't take it upon yourself to learn about it, you're not going to be in a position to be an informed, expert faculty member."

Training out of synch with the science

As a result of the training deficit, health care providers themselves often perpetuate weight stigma or misconceptions about how best to treat patients who have it.

The standard medical curriculum also hasn't kept pace with research about obesity, which has transformed the field in recent decades. It is now understood to be a complex disease involving many of the body's systems. Factors like genetics, hormones, sleep quality and even stigma can cause weight gain. Treating it, therefore, often requires more than just restricting or burning calories.

New and promising — if very expensive — medications that act on the areas of the brain that regulate appetite underscore that obesity, like many other illnesses, can be treated with drugs, rather than will power alone.

It's hard to challenge old notions about obesity in medical training because classes tend to focus on specific organ-based disciplines, like cardiology or endocrinology — but obesity crosses over many different categories. It tends to get mention a few minutes here and there, and only in the context of other diseases, not as an overarching disease of its own, Kushner says.

Also, "there's a prevailing bias that this is a soft science; this is not something we need to teach and people just need to take better care of themselves," he adds.

The result, he says, is most physicians aren't equipped to help patients with obesity.

That's something Tong Yan witnessed first hand. Yan, now in his fourth year of medical school, recalls one of his supervising doctors talking to a patient with pressure headaches related, in part, to complications from obesity. Yan says the doctor was rushed — and was speaking to the patient through a translator, which took twice as long. And he then reprimanded the patient, saying things like, "You need to get out and exercise. You can't just sit around," or "Don't you know this is an issue?"

Yan recoiled from the exchange. He knew that ran counter to what he'd learned in obesity and bias training. But the doctor's seniority scared both Yan and the patient into silence, without challenging the tone or content of the lecture.

"I am ashamed to say that I didn't really say much," Yan admits. "It was just an observation that left a big impact."

Patients suffer from physician's ignorance

The impact is deep for patients like Patty Nece, who in her 64 years says she's never been free from the stigma of living in a large body. She gets catcalled, compared to cows or whales — insults that amplify her own savage inner voice.

"I'd sorta become my own worst enemy, my own worst bully," she says. "I won awards as an attorney and I've been active in community and nothing overcame all the weight bias and stigma I'd faced."

But, she says, the biggest clinical damage has come from doctors themselves, including from an orthopedist she consulted several years ago about hip pain.

Almost immediately, without listening to her, examining her or even touching her, she says the doctor launched into a lecture about her excess weight, attributing her pain to obesity.

"He said, 'See, you're even crying because of your weight,' which was so far from the truth; I was crying because of him," Nece says. "I didn't want to see another physician in my life."

When she finally did see someone else for her hip pain, the root cause turned out to be a severe curve in her spine. Nece says health care workers often seem to assume that people with excess weight don't know their bodies, even though it's something she thinks about all the time. She says the orthopedist wasn't alone in dismissing her; she's felt spurned for her weight by others, too — dieticians, mammographers, rheumatologists.

That kind of alienation is especially harmful among racial minorities, where disparities in care already create many challenges. That's true also of obesity care in Black and Latino communities, where rates of obesity run highest, yet people are underdiagnosed and undertreated.

Kofi Essel, a pediatrician and nutritionist in Washington DC, says often young doctors aren't coming from the same kind of backgrounds as those who tend to suffer from obesity. They don't understand how things like neighborhood design, food insecurity, and access to fresh produce contribute to obesity.

"Why? Because most of us in medical education come from middle- to upper-income backgrounds, so there is oftentimes economic discordance with many of our patients," Essel says.

He argues the solution, again, is to increase training in obesity — not only the science of it, but also in how to talk to patients with compassion and without stigma. Essel also directs the obesity summit at George Washington University, and says he's seen it transform the way students think about obesity. "Their new awareness, their new knowledge, their new attitude, their new behaviors is night and day," he says.

Student Tong Yan agrees. He intends to become a family physician in urban areas underserved by medical care.

"I'm particularly motivated to improve these kinds of skills for the sake of my patients in the future," he says.