Dr Croskerry said obesity bias was prevalent in society
Patients who are obese may avoid seeking life-saving treatment as they fear being judged about their weight by medical staff, an expert has said.
Dr Pat Croskerry said some people avoid or delay treatments such as routine cervical screening examinations for fear of being judged about their size.
The professor said some who seek help do not always get treated because of "obesity bias" from clinicians.
He will speak on the issue at a conference on obesity in Edinburgh.
The professor of emergency medicine at Dalhousie University in Canada will tell delegates that "obesity bias" was common among medics, including those specialising in obesity.
Other studies have shown that some doctors and health professionals have clearly associated the stereotypes of "lazy", "stupid" and "worthless" with obese people.
Dr Croskerry said it was important that medical staff put their feelings on the issue aside.
"Obesity bias is prevalent in society, including within medicine," he said.
"While doctors and other health professionals are human and are subject to a range of emotions and prejudices, it is vital that such prejudices are not allowed to influence clinical decision-making, as obese patients can be placed in double jeopardy.
"If we wish to ensure that obese patients receive the best quality of care, be it for a chronic obesity-related condition or in an emergency situation, and do not experience inequalities of treatment due to their size, medical staff need to avoid blaming or judging obese patients and concentrate on how to best treat them."
The conference will also hear from surgeon Duff Bruce, that only 1% of the 24,000 severely obese Scots patients who would benefit from gastric bands have been offered the surgery.
About 300 people a year undergo the treatment, which can cure Type 2 diabetes and reduce cases of obesity-related high-blood pressure and coronary artery disease.
Mr Bruce has called for the treatment to be made more widely available.
"Bariatric surgery is very cost-effective and, if made more widely available, could significantly reduce the cost to NHS Scotland of treating a range of obesity-related chronic diseases," he said.
Doctors attending the conference will also hear presentations on obesity in pregnancy and labour.
Obesity has now reached epidemic levels in Scotland, and are the second highest in the developed world, trailing only the US.
The conference has been organised by the Royal College of Physicians of Edinburgh, the Royal College of Surgeons of Edinburgh and the Royal College of Anaesthetists.