Dr Sarah Jackson, from University College London, was commenting after a new study found that experiences of weight discrimination account for approximately 40% of the negative psychological effects associated with obesity.
Jackson - who was lead author of the study - believes the law in the UK should protect people against fat-shaming.
“In the United Kingdom, the Equality Act 2010 legally protects individuals from discrimination on the basis of age, sex, race, disability, religion or beliefs, sexual orientation, marital status, pregnancy, or gender reassignment, making it clear that discriminatory behaviour of this nature is not to be accepted,” she said in a statement.
“However, our results indicate that discriminatory experiences contribute to poorer psychological wellbeing in individuals with obesity, but there are currently no laws prohibiting weight discrimination.
"This might send the message to people that weight discrimination is socially acceptable.”
The study of over 5,000 UK adults - which was funded by Cancer Research UK - asked participants questions to ascertain whether or not they had experienced weight discrimination.
The researchers listed being treated disrespectfully, receiving poor service in shops and being harassed as some examples of discrimination.
Psychological wellbeing of participants was assessed, as well as overall life satisfaction.
Results indicated that those who felt discriminated against on the basis of their weight had a 70% increase in symptoms of depression and a 14% drop in quality of life.
Those who had experienced fat-shaming also reported 12% lower life satisfaction than those who did not believe they had experienced any form of weight discrimination.
Professor Jane Wardle, director of the Cancer Research UK Health Behaviour Centre at UCL, said: “Combined with our previous work showing that weight discrimination does not encourage weight loss, we can see that weight discrimination is part of the obesity problem and not the solution.
"Weight bias has been documented not only among the general public but also among health professionals, and many obese patients report being treated disrespectfully by doctors because of their weight.
"Everyone, including doctors, should stop blaming and shaming people for their weight, and offer support, and where appropriate, treatment.”
Jackson and Wardle are not the first people to warn about the psychological effects of fat-shaming.
Last year, plus-size magazine SLINK condemned weight loss expert Steve Miller for suggesting the UK should have an annual 'warn a friend they're fat day'.
Blogging on HuffPost UK Lifestyle at the time, SLINK editor Rivkie Baum pointed out that if a person is overweight, they probably already know. Fat-shaming never helps anyone.
"Fat people are reminded as they walk along the street, past store windows and stores they can not shop in," she said.
"Binge eating is as much of a mental health issue as anorexia and bulimia. Brushing these issues under the carpet is dangerously naive."