The struggles of the disadvantaged resonate with Bleich. The daughter of two public schoolteachers from inner-city Baltimore, Bleich and her family relied on food stamps for a time to make ends meet. She was close to her paternal grandparents — who once lived on New York City’s swanky Upper East Side — and to her maternal grandfather, a Maryland corn farmer who grew up poor and illiterate. Several years after completing a degree in psychology at Columbia University in 2000, she opted to pursue a Ph.D. in health policy at the Harvard Graduate School of Arts and Sciences. En route to Massachusetts, Bleich stopped at her grandfather’s farm. He beamed about Harvard but cautioned, “Don’t get too uppity.”

She didn’t get his meaning until months later, when she found herself working on theoretical research topics with little chance of affecting people in the real world. So she decided to study obesity — an issue that begs for workable and practical solutions. “I want to answer the ‘So what?’ question,” she said. “I have yet to come across someone — on a bus, on a plane, on a train — who hasn’t struggled with their weight or known someone who has. I have not had personal weight challenges, but my mother lost a lot of weight and kept it off for 20 years. All of us have stories, and you can learn a lot by talking to people about their stories. The science is one thing, but weight is a very personal issue.”

Bleich phoned her “corn farmer grandpa” to say that she’d decided to study obesity. “You’re going to make fat people thin?” he said. “I told him, ‘You cannot call people fat, but yes, I am going to help people try to lose weight.’ He said, ‘Baby, I think that’s wonderful.’”

Earlier this year, following weight-loss surgery, the author Roxane Gay recounted her struggle with the psychological underpinnings of overeating. Gay and others — such as the anonymous blogger with tens of thousands of followers who calls herself Your Fat Friend and Ashley Graham, Sports Illustrated’s first plus-size swimsuit cover model — have written about body shaming in America.

One message they sometimes convey is that it’s possible to be fat and healthy. Your Fat Friend claims that although her body mass index (BMI) puts her in the realm of the “super morbidly obese,” her indicators are normal. According to a 2016 study in the International Journal of Obesity, a significant percentage of overweight or clinically obese people are, in fact, metabolically healthy. But Bleich wants to be clear that she’s not talking about whether it’s possible for some weight-challenged individuals to have normal blood pressure, cholesterol, and insulin levels.

“BMI is an imperfect measure, but there are mountains of literature from epidemiology and other disciplines which say that as your BMI goes up, so too does your risk of all sorts of health conditions,” Bleich said.

The danger of celebrating large bodies is that, “It implies it’s OK to be large from a health perspective, and it’s not,” she said. “But we know that stigma can be a real deterrent to seeking help and trying to actually lose weight. And so there’s this delicate balance between reaching out to people who have trouble with their weight and making them feel bad in the process” — as with the flight attendant and the cranberry juice-drinking airline passenger.

“Obesity exists. It’s getting worse,” Bleich said. “The solution to obesity does not lie with you or me. It does not lie with individuals. Yes, there are people who will get it together and will actually be able to lose weight and keep it off. But the fact that we have a $66 billion diet industry demonstrates that we’re forever falling off the wagon.

“There aren’t obvious solutions. There’s no pill that can fix it. Public health has limited reach and resources. I think the goal is finding sweet spots where the food and beverage industries maximize shareholder dollars but also maximize the population’s health.”

One such sweet spot might be making healthful beverages and sides the default in fast-food kids’ meals and adult restaurant combo meals — swapping a no-calorie beverage and salad or fruit, for example, for sugary beverages and fries. If restaurants don’t lose revenue from the switch, this could be a win-win. “Changing defaults can be a powerful public health tool, because diners tend to stick with whatever comes with a combo deal rather than change it for something else,” Bleich said.

There’s big money at stake: Americans spend half their food dollars on meals outside the home. But Bleich notes that the entire state of California, along with Baltimore and other cities, have already passed bills mandating healthful beverages as the default for fast-food kids’ meals.

“It’s going to take multiple efforts working effectively together to actually move the needle,” she said. “But progress is possible.”

This story originally appeared in Radcliffe Magazine’s winter 2019 issue.

Deborah Halber is a freelance journalist.