Whether these routine denials violate anti-discrimination laws is unclear, especially since the degree to which obesity is a legally protected disability remains unsettled. Industry specialists argue the law is unambiguous.

“Nursing homes aren’t required, like emergency rooms, to admit patients, so they have a lot of latitude,” said David Grabowski, a professor of health-care policy at Harvard Medical School.

But some experts argue that severely obese patients with significant physical impairments could challenge their denials.

“That’s what the Americans with Disability Act is meant to protect against,” said Eric Carlson, a lawyer for Justice in Aging, a legal-advocacy group.

Legal experts say the question is far from settled, but in at least one instance, a severely obese patient who was denied admission to a nursing home filed a discrimination complaint through the federal Office for Civil Rights. To resolve the issue, the nursing home, the GlenShire Nursing and Rehabilitation Center in Illinois, admitted the patient and provided an extra-wide dialysis chair.

The reluctance to accept hospital referrals, especially when physical therapy or wound care is needed, comes down to practical matters: How many staff members will it take to turn the patient? Where is the wound? How long will physical therapy take?

“We ask them, ‘What is the barrier?,’” said Akofa Bonsi-Wallace, the former director of discharge planning at the University of Alabama at Birmingham hospital, who often reached out to nursing homes in Georgia, Florida, and Tennessee. “Most of the time it’s staffing. We’ve heard, ‘I already have a morbidly obese patient, and they are eating away at my staffing hours.’”

But it’s not only the size of nursing-home patients that is changing.

Nursing-home administrators say some of their extremely obese residents are young adults or middle-aged men and women stricken by congestive heart failure, stroke, or facing complications from surgery or an accident. They can’t return home or to an assisted-living facility because the requirements to safely care for them are too great.

Lee Nalls, 28, awoke during the night at his mother’s house in North Port, Alabama and noticed his face felt weak. As he made his way to the bathroom, he fell and remembers hearing his mother call the paramedics. A diabetic and severely obese since childhood, Nalls had suffered a stroke that left his right side paralyzed.

“I can barely move,” he said, his speech slurred and his eyes listless.

With a lunch tray of beef enchiladas and salsa salad in front of him, Nalls slouched in a wheelchair in his room at Generations of Red Bay in Alabama. Like his fellow residents in the special unit for obese residents, Nalls opts to eat alone instead of the cafeteria.

“I’m not really comfortable around other people,” Nalls said, his Southern politesse unhardened by the gravity of his situation. His classmates in grade school ridiculed him about his weight: “Kids would stick notes on my back pack as I walked past, and it made me feel sad,” he recalled. Coming under the gaze of other residents is “just something I don’t want to deal with.”