I was a fat shamer. But not anymore.

The start of a recent conversation with a 13-year-old client - considered obese by body mass index (BMI) standards - illustrated my change of heart.

"People aren't meant to be this large," she said of herself in a matter-of-fact tone. It sounded like she was imprisoned in shame and saw no way out.

As a therapist specializing in helping people with eating disorders, I had begun her treatment plan with the usual focus on weight loss. But it was her feelings of shame, and mine for maybe contributing to them each time I coaxed her to set diet and exercise goals she wouldn't meet, that made me rethink the purpose of her therapy.

Wouldn't it be better to help her plan how she wants to live and enjoy her life with the body she has rather than live in shame because of it?

I'm aware of the latest research questioning whether you can be both fat and fit (see sidebar), but health is more than being able to run on a treadmill. In my practice and in published research, I have seen that people mired in self-loathing over their size don't fare well physically, psychologically, socially, or professionally.

Maybe it's time for a different strategy.

I grabbed my iPad and went to danceswithfat.org, a website I learned about at the Renfrew Eating Disorder Foundation's annual conference in Philadelphia last month. Together, we watched a video of Ragen Chastain dancing the West Coast Swing to Bette Midler's "I'm Beautiful." Chastain is a writer, athlete, entrepreneur, two-time dance competition winner, and has no plans to reduce her generous frame.

"Fat is a perfectly good adjective to describe me," she said in a phone call from her home in Los Angeles.

Chastain said she became a "fat activist" after a ballroom dancing competition judge told her she "couldn't stand to look at me."

She had already accepted that, like most people, she was unlikely ever to lose weight and keep it off permanently. So instead of her usual yo-yo dieting, she decided to focus on healthy behaviors like eating more vegetables, drinking a lot of water, sleeping well, and exercising. She dances, runs, bikes, and swims.

"I used to practice dieting to be someone other people wanted me to be - focusing on what, when, and how I ate, but it never made me healthier, happier, or thinner," she said. The switch happened after reading Health at Every Size by psychologist Linda Bacon, whose compilation of research about the myths surrounding weight and dieting was liberating.

"There are people who hate themselves and their bodies because they don't think they have another choice," she said.

Some people believe that if an overweight person gives up dieting, it means giving up on health. Chastain says that for her, it's just the opposite.

In truth, losing weight and keeping it off is unlikely for most people. Even the best-established diets have an 80 percent failure rate in the long term.

Yet, someone like my young client who has an aversion to her shape will have trouble loving her body and wanting to care for it, said Kathy Kater, a Minnesota psychotherapist who spoke on the topic at the conference.

"There is plenty of evidence that the less a person worries about weight, the better care they take of themselves - including leading more active, enjoyable lifestyles - which may or may not lead to weight loss," Kater said.

Working with my client to set her own goals exclusive of what she looks like became more important than pushing her to lose weight.

Kater believes mental-health professionals should share research about health at every size with their clients.

"First we have to look within ourselves and work on our own biases," she said. "Then we share what we learn about the misconceptions about fat with family, friends, clients, physicians, nutritionists, and school nurses - even offer to give a presentation to the local PTO. BMI, for example, is considered a health assessment when, in fact, it is only a ratio of weight and height."

A new notion to contend with is "thin privilege" - an assumption of health, happiness, and success just because someone is slender. It stands in contrast to a quick judgment that overweight people are in poor health and unproductive.

Active obese individuals actually have lower morbidity and mortality than normal-weight individuals who are sedentary, and the health risks of obesity are largely controlled if a person is active and fit, according to the National Institutes of Health.

"Life is not better if you are skinny. Life is better in a culture that doesn't make me feel bad because I am fat," said Colorado psychotherapist Carmen Cool, who spoke at the conference about harmful assumptions and body shaming among teens.

At the end of the conversation, my 13-year-old client was much more uplifting as she thanked me for sharing the website and felt she might be mistaken about what sizes people are meant to be.

Me, too.

Diane Girardot is a writer and psychotherapist in Chadds Ford and Philadelphia.

What science says about fit vs. fat debate

Whether it's possible to be both fat and fit has been a hotly debated topic for years.

The latest: A study of 1.3 million Swedish men found that over 30 years, normal-weight men at any level of fitness had a lower risk of premature death than the most physically fit obese men, researchers reported last month in the International Journal of Epidemiology.

The study wasn't designed to prove cause and effect, however - simply an association between fitness and the risk of premature death.

There are plenty of data connecting obesity with diseases, from cancer to heart disease to diabetes. Yet many other studies prove what dieters already know - it's extremely difficult to lose weight and keep it off permanently.

But there's some positive news, too. Numerous researchers have found that interventions beyond traditional weight-loss diets - such as improved nutrition, getting more activity, and challenging the negative myths and assumptions related to size - have powerful benefits.

What doesn't work: Nagging, shaming, and blaming obese people for their size.

Among the research findings:

Modest changes in eating, activity, and weight can help normalize the metabolic profile of obese people, according to a 2013 study published in the New England Journal of Medicine.

Intuitive eating - defined as eating only when hungry, stopping when full, and choosing foods according to personal preference - is associated with both lower BMI and better psychological health, according to a review of literature on the subject last year in the journal Public Health Nutrition.

The chronic stress of weight loss and gain, plus feelings of shame over weight, are associated with high cholesterol and blood pressure as well as insulin resistance, a study published in the Journal of Community Health found.

Simply knowing the health risks of obesity often does not increase efforts or success in losing weight (Nutrition Journal, 2011).

Obese people who are led to believe they will be happier and healthier if they diet and exercise frequently experience only more guilt, blame, shame, and feelings of failure, a 2010 study in the journal Public Health found.

- Diane R. Girardot