Overweight workers find it harder to get jobs than their slim counterparts, an online survey suggests.
Overweight people were said to lack self-discipline
The magazine survey of 2,000 personnel officers found most preferred to offer jobs to workers of a "normal weight".
Half of those polled by Personnel Today thought obesity affected productivity. A similar number believed overweight people lacked self-discipline.
The magazine's editor Karen Dempsey said it suggested hidden discrimination and overweight people were missing out.
She said: "To date, obesity has not been given the same recognition as sex, age, disabilities and race discrimination.
"But as our survey shows, overweight workers are being marginalised and given fewer opportunities than their slimmer counterparts."
The survey also found that one in 10 personnel officers would not want an overweight employee to meet a client. The same percentage believed they could sack a worker for being obese.
Ms Dempsey added that a "clearer definition of obesity" was needed to help businesses understand how it "truly affects" workplace performance.
Ben Willmott, from the Chartered Institute of Personnel and Development, told BBC News most employers choose people on the basis of ability, but added that weight is a "small aspect" which some employers take into account.
"When employers make a decision to employ someone, they want to bring someone on board who is going to be a productive and engaged individual," he said, explaining that some employers may have health concerns about overweight candidates.
But Mr Willmott added: "I think most employers treat people as individuals and recruit them on their ability to do the job rather than how much they weigh."
Meanwhile, Daniel Thomas, Personnel Today deputy editor, said there was little protection for overweight employees.
Mr Thomas said: "There's no such thing as fattism yet.....but if an obese person can prove they're actually disabled - so for example they've got dyslexia or they're depressed - then they can take that to an employment tribunal."