“Just because the picture of a disease looks similar doesn’t mean there is one cause.”

In some people obesity may even be caused by a virus. Dhurandhar’s recent research has focused on viruses that effect weight. He told me about a virus called adenovirus-36 (or Ad-36), which can increase fat cell production in some people and make fat cells fatter, potentially leading to the disease.

While diet and lifestyle certainly play a role in influencing a person’s weight, assuming that a person’s eating and exercise habits are the reason—or the only reason—for their obesity is misguided, say the experts. Some people face a much harder battle to keep off the pounds, or suffer from extenuating circumstances that make healthy living challenging.

“People feel that because everybody eats, they can comment on it,” said Dhurandhar, “but just because you eat everyday doesn’t mean you understand nutritional science.”

***

In her fat-shaming rant, Arbour says, “I really hope this bomb of truth makes you want to be healthier.” After talking to obesity experts, however, it’s clear obesity is not simply a “calories in / calories out” disease—and yelling at someone to lose weight doesn’t help.

Dhurandhar said he hears stories about these kinds of unhelpful “truth bombs” being hurled at his patients all the time. “Some people tend to think, ‘All I’m going to do is to tell someone that their BMI is this, and magically, they are going to start to losing weight,” he said, stressing that this approach simply does not work.

“Who needs to tell them this? All of us have mirrors, all of us know where we should be. The sad reality is that people know what their BMI is. They may be doing something about it, and they may not get anywhere. Treatment has not been successful in many individuals, and those who are successful don’t always maintain that body weight,” he said. “How unfair it is to point the finger at someone, and say, ‘Hey, why don’t you do something about it.'”

(Of course, pop culture is filled with examples of weight-loss professionals doing just that, which reinforces obesity myths. On the NBC reality show The Biggest Loser, for example, coaches shout at contestants while dramatically slashing their calorie intake and upping their exercise—attributing their obesity mostly to bad habits. Many contestants gain the weight back after the show ends, however, suggesting the underlying cause was never treated.)

Michael Jensen, a professor of endocrinology, diabetes, metabolism, and nutrition at the Mayo Clinic, told me that most of his patients are aware their weight is a problem. Yet even with that awareness, they struggle to lose the pounds. “Some have surgery and they still can’t make the behavior changes they need to,” he said. “But that means there could be something [else] going on there: behavioral, hormonal, or psychological.”

Notably, Jensen said he’s seen other patients who have a much easier time losing weight. So what’s the difference between the two groups? “I’d love to know the answer to that question,” he told me. Until science provides those answers, he advises “not to lump everyone together who has a weight problem.”

***

In order to really combat obesity, experts agreed that we need to work to stop the disease before it starts—on both an individual and societal level. “When you look at other things, like smoking and seat belts, it wasn’t [just] individual efforts,” said Jensen. “We agreed as a society that this is important.”

First Lady Michelle Obama has made it her mission to teach kids healthy eating and exercise habits with her Let’s Move! campaign, which may help young people make smarter choices about the contributors to obesity that are in their control. Obesity experts also advised that restaurants list calorie counts on their menus and cut down portion sizes—and that companies incorporate exercise and wellness programs into the work day and provide access to healthy food.

As individuals, if we find ourselves struggling, the experts recommended seeking out medical and psychological help—and offering help to those who are struggling. None of their recommended tactics include fat shaming.

Hey, Arbour—you catch all that?