New York City has passed a bill outlawing discrimination based on weight, joining a growing movement in the US to make size a protected trait on par with race and gender.
More than 40% of American adults are considered obese and studies show weight stigma is pervasive.
The bias can bring sharp costs, such as lower wages, especially for women.
City Councilman Shaun Abreu said weight discrimination was "a silent burden people have had to carry".
During public hearings, supporters cited difficulty navigating seating at restaurants and theatres, getting turned away by landlords, and butting up against weight limits on the city's bike sharing programme.
Councilman Abreu, who sponsored the bill, said he became more aware of the issue when he gained more than 40lb (18.1kg) during lockdown and saw a shift in how he was treated. He said the lack of protections had amplified the problems people face.
"They're being discriminated against with no recourse and society saying that's perfectly fine," he said.
The measure is expected to be signed into law by New York's mayor later this month. The effort received widespread support, passing 44-5, despite scepticism in some quarters.
New York City council's minority leader, Joseph Borelli, who is a Republican, told the New York Times he was worried the law would empower New Yorkers "to sue anyone and everything".
"I'm overweight but I'm not a victim. No-one should feel bad for me except my struggling shirt buttons," he said.
Michigan has barred workplace discrimination based on weight since 1976 and a handful of other cities, including San Francisco and Washington DC, have legislation on the books.
State-level bills have now been introduced in New York, Massachusetts, Vermont, and New Jersey.
The efforts follow a dramatic increase in obesity rates over the past 20 years.
Tegan Lecheler, advocacy director for the National Association for the Advancement of Fat Acceptance, which worked with Councilman Abreu on the New York City bill, said she hoped the measure would "encourage a larger conversation of framing this beyond health".
"It's not a health issue. It's a civil rights issue," she said. "This is really about if people are safe and protected and have the right to be in spaces."
New York's human rights law already bars discrimination in housing, the workplace and public accommodation based on 27 characteristics, including age, marital status, disability and national origin.
The bill adds weight and height to that list, while including exceptions for jobs in which weight and height are a "bona fide occupational qualification" or where there is a public health and safety concern.
Councilman Abreu said he hoped the move by the largest city in the country would encourage other cities and states to follow suit.
"We want this bill to send a message to everybody that you matter, regardless of if you're above or below average weight," he said. "That's why we pushed this."