Last year Dr Christine Knight was given £177,000 to investigate the impact of negative stereotyping in the Scottish diet.
She believes the deep-fried chocolate treat acts as a 'lightning rod' for social issues, including class prejudice and English attitudes towards Scots.
And now she has said its similarity to bodily fluids, and its phallic form, add to the stigma.
Speaking ahead of an important food conference this week, she said: “Our disgust response to certain foods can relate to their resemblance to bodily fluids and body parts, especially faeces, pus, vomit and genitalia.
“The deep-fried Mars bar combines visual and textural similarities to all of these elements in a single package, with partially melted chocolate, oozy caramel, pale lumpy batter and a phallic profile.
“It has become shorthand for poor Scottish nutrition, health and obesity rates, simultaneously communicating derogatory messages about taste, class, morality and the Scottish nation itself.”
She also claims that, like the haggis before it, jokes about the deep-fried Mars bar emerged during a period when the relationship between Scotland and England had been changing and uneasy.
Similar stereotypes were peddled around the time of the Act of Union in 1707, the Jacobite Rising in the 1740s and the appointment of the Earl of Bute as Britain’s first Scots-born Prime Minister in 1762.
“This may partly explain why the late 20th and early 21st centuries, with the establishment of the Scottish parliament and the recent referendum on independence, have seen negative stereotypes of the Scottish diet re-emerge so strongly,” she said.
“The haggis was just one of a range of culinary stereotypes and metaphors that was used to stigmatise and satirise the Scots.
“Now the deep-fried Mars bar has replaced haggis in political cartoon and satires about Scotland.”
Dr Knight is set to give a talk at Scotland’s Foodscape, organised by Queen Margaret University, later this week.
The claims come amid efforts by the Scottish government to build up its food and drink sector and its commitment to becoming a “good food nation”.
According to Dr Knight, the latest stereotype has shifted beliefs in an unhealthy direction - as some young people from ethnic backgrounds see eating deep-fried Mars bars as a way of “claiming” Scottish identity.
Chris Corvi, who works at Guido’s Coronation Cafe in Glasgow’s East End, sells the chocolate snacks for £1 each.
He said: “It’s only tourists and foreign students who ask for it. When they arrive here they expect us all to be eating deep-fried Mars bars, drinking Irn Bru and wearing Kilts.
“But who cares? It’s all part of the fun.”
James Withers, of Scotland Food and Drink, said the notion that the deep-fried Mars bar represented culinary Scotland was a “tired joke now”.
