'Obesity' should be defined by a person's health, not just their weight, Canada doctors say

• "Obesity," long defined using a ratio of height to weight, should be defined by someone's health, new Canadian guidelines say.
• The guidelines emphasize that weight and body fat aren't necessarily indicative of poor health, and that the old model perpetuates weight stigma.
• The new guidelines offer five steps clinicians should take when addressing patients with obesity, starting with asking if they want to talk about their weight.
• While some experts say the update is a step in the right direction, others say it doesn't go far enough.

From a young age, going to the doctor was a scary concept to Lisa Schaffer. Not because it meant she might get stuck with a shot, but because she knew the focus would be her weight. It always was.

Even when Schaffer tested negative for conditions like Type 2 diabetes, she was left with the impression that her size was her fault — and it was her duty to find a solution.

The message was: "Until I figured that out, I really wasn't worthy of care and attention for any health concern," Schaffer, now an adult who works at Obesity Canada, said in a podcast hosted by the Canadian Medical Association Journal (CMAJ).

Many people with obesity have similar stories, but updated clinical guidelines published in CMAJ Tuesday advise doctors in taking a new approach: One that defines obesity not as a ratio of height to weight, as has long been the case, but as a chronic disease in which excess body fat impairs health.

The authors say the change reflects that people can have excess body fat but still be healthy, that eat-less-move-more approaches to weight loss often backfire, and that weight stigma in healthcare is a health risk in itself.

"For the longest time, we blamed our patients, we blamed people living with obesity for the lack of willpower in terms of overeating, in terms of not being physically active," co-author Dr. David C.W. Lau of the University of Calgary's Julia MacFarlane Diabetes Research Centre, said in the podcast. "We now know this is a totally misperceived perception."

The guidelines recognize BMI's flaws

The new guidelines, which were developed including input from people with obesity including Schaffer, define obesity as "a prevalent, complex, progressive, and relapsing chronic disease, characterized by abnormal or excessive body fat (adiposity) that impairs health."

The strays from the long-held and highly criticized definition of obesity as a BMI, a height-to-weight ratio, of over 30. That means a 6-foot, 225-pound person is considered obese, whether that person is a muscle-strapped athlete or a junk food fiend who's developed non-alcoholic fatty liver disease.

Under the current guidelines, the term would only apply to people who have a high BMI and a connected physical or mental health condition.

The change is based on new knowledge of obesity's complicated causes and potential repercussions.

"It's simplistic to think that obesity is just a matter of not being physically active and overeating," Lau said. "In fact, obesity is caused by a very complicated interplay of genetic, metabolic, and behavioral, as well as environmental obesogenic factors."

The guidelines outline five steps

The new model recommends doctors address obesity in the clinic using five steps. The first is simply asking patients if their weight is something they'd like to discuss.

That's the most important step because it makes the patient a partner, not a victim of weight stigma, co-author Dr. Sean Wharton of Hamilton's McMaster University said on the podcast. "If we can't get past bias and stigma, the other steps don't really work."

Next, healthcare providers "assess their story," or take a history to understand potential underlying causes, the patient's goals, and in some cases do tests to identify potential health complications like high blood pressure or pre-diabetes.

During the third step, "advise on management," clinicians focus on tailoring the patient's diet to the medical conditions they're looking to treat (with a focus on nutrition not calorie-counting) and encourage at least 30 minutes of movement a day.

While nutrition and exercise don't tend to cause significant weight loss, even modest weight loss or none at all can improve the patient's health. If it doesn't, other therapies can be considered, like psychological support, medications, and surgery.

The fourth and fifth steps, to "agree on goals" and "assist with drivers and barriers" are meant to support the patient in long-term management of their chronic disease.

Some professionals say the guidelines don't go far enough

Sylvia Ley, an assistant professor in the department of epidemiology at Tulane University who was not involved with the report told CNN the guidelines are an "excellent upgrade."

But other health professionals and body-positive advocates say they don't go far enough.

Registered dietitian Rebecca Scritchfield, for one, told Insider the guidelines "still point to individual bodies as the problem, not culture."

She said they're still based on the false belief that more body weight causes (not simply correlates with) disease, when the more likely reason some of her higher-weight clients also have health conditions is weight stigma.

"Why divide people by size at all?" Scritchfield, author of "Body Kindness," said. "Thin people and fat people can have similar behavioral difficulties with mindful self-care and need a combination of psychological support and medical nutrition therapy."

Medicine needs to become weight-neutral, she said, and the guidelines fall short. Her message: "Give patients respect regardless of their size and tune into the social factors such as poverty, racism, and trauma that may make mindful self-care difficult."

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