When Anna Guest-Jelley—26 years old at the time—badly twisted her ankle, the Nashville native went to see her doctor. "Your ankle's probably swollen," she said, "because you're carrying extra weight."

Guest-Jelley, a yoga teacher, went along with her diagnosis. When the doctor reported that Guest-Jelley's x-ray didn't show any fractures, she returned home with instructions to ice her foot—and an all-too-familiar feeling of humiliation at the physician's focus on her size. "Almost every time I've ever gone to a doctor's appointment, I've experienced some level of shaming because of my weight," she says.

Her experience is shockingly common. Weight stigma is on the rise in America, according to the Rudd Center for Food Policy and Obesity at Yale University, and, ironically, nowhere is it more deeply rooted than among health care providers. Multiple studies have found that doctors, med students, nurses, dietitians, and other health care professionals routinely stereotype their heavy patients. In landmark 2003 research from the University of Pennsylvania, for instance, more than half of the 620 primary-care doctors surveyed characterized their obese patients as "awkward," "unattractive," "ugly," and "noncompliant"—the latter meaning that they wouldn't follow recommendations. More than one-third of the physicians regarded obese individuals as "weak willed," "sloppy," and "lazy."

And it's women who bear the brunt of this characterization—even when they're not obese. Doctors' weight prejudices start when a female patient is as little as 13 pounds overweight—meaning her body mass index would likely be around 27—found a 2007 study from Yale University. (BMI is a measurement that uses a ratio of height to weight to categorize people as being of normal weight [18.5 to 24.9], overweight [25 to 29.9], or obese [30+].) "For men, the bias doesn't kick in until around a BMI of thirty-five, approximately seventy-five pounds overweight," says Rebecca Puhl, PhD, director of Research and Weight Initiatives at the Rudd Center. "That's a definite gender difference."

Many doctors argue that, overall, they do a good job of attending to all their patients equally. Indeed, a 2010 University of Pennsylvania study established that despite the clear weight bias among doctors, they recommended the same treatments for a specific list of conditions—including diabetes and certain cancer screenings—regardless of a patient's size or BMI. However, the study didn't consider other complaints associated with obesity (such as joint pain and shortness of breath), and it looked mostly at older men, who are less likely to experience weight bias.

What's more, the study didn't examine whether there was any difference in the way physicians communicated medical recommendations to their patients of different weights—and that may be just as key. "One of the most important parts of the medical relationship is the patient feeling able to ask questions and being comfortable with the doctor's advice," notes Dr. Huizinga.

Treating obesity, however, is uniquely challenging. Ninety-five percent of people who lose weight gain it back within 3 to 5 years—which may leave physicians feeling frustrated and helpless and perhaps inclined to blame patients. "When a person has cancer that recurs, the physician is so empathetic," Dr. Sharma says. "But when a person regains weight, the response is disgust. And that's morally and professionally abhorrent."

When doctors take courses that emphasize "uncontrollable" causes of obesity, such as genetics or certain medications, their weight bias diminishes. But, although medical school curricula are expanding, most physicians who are practicing today received little training on weight issues.

MORE: 6 Health Problems To Never Ignore

Patient advocacy groups such as the Association for Size Diversity and Health and the National Association to Advance Fat Acceptance argue that since obesity has been so stigmatized and is so difficult to treat, doctors should be taught to focus less on weight itself and more on other indicators of health, pointing out that even overweight people can be otherwise healthy. They cite studies like the one published in the Journal of the American Medical Association in 2005 that found that people considered overweight (with BMIs of 25 to 29.9) actually had lower mortality rates than those viewed as being of normal weight. And some advocates also feel that whether weight is mentioned at all should be up to the patient.

But there are also doctors who are strongly committed to avoiding the pitfalls of obesity prejudice—while still addressing weight head-on. "The first thing that comes out of your mouth when you meet a patient can't be 'You're obese,' " says Juan Rivera, MD, a preventive cardiologist and an assistant professor at Miami School of Medicine.

"You have to wait for the right moment, and be prepared to work together for a long time. Fighting obesity is a marathon, not a sprint." Above all, Dr. Rivera says, it takes sensitive, honest communication.

For women who feel that their doctors treat them with less dignity due to their weight, experts, including Dr. Rivera, advise telling the physicians, calmly, what they perceive as biased behavior and how they feel about it. "Ultimately, both parties will benefit," says Dr. Rivera. "And if your physician doesn't take the criticism well, it might be a good time to switch doctors."

Finding a new provider can make a world of difference. After Tretola's doctor dismissed her swollen legs, she scheduled a physical with a new practitioner. "The doctor asked if I wanted to be weighed, and I said, 'I'd prefer not to today,' " Tretola reports. "That was fine with him. We did talk about weight, but he was very welcoming, not judgmental, and he discussed problems—such as my high cholesterol—without blaming my weight.

"It was so refreshing."

MORE: How To Respect Your Body (And Get To A Healthy Weight In The Process)

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io