To come to this conclusion, researchers conducted an Internet survey of 600 overweight and obese adults in the United States who made regular visits to their primary care doctor.
"Negative encounters can prompt a weight-loss attempt, but our study shows they do not translate into success," study author Dr. Kimberly Gudzune, an assistant professor in the division of general internal medicine at the Johns Hopkins University School of Medicine in Baltimore, said in a Hopkins news release.
"Ideally, we need to talk about weight loss without making patients feel they are being judged," she said. "It's a fine line to walk, but if we can do it with sensitivity, a lot of patients would benefit."
The researchers found that 21 percent of the respondents said they believed their doctor judged them because of their weight. Ninety-six percent of those who felt judged said they tried to lose weight in the previous year, compared with 84 percent who did not feel judged.
Only 14 percent of people who felt judged and discussed weight loss with their doctor lost 10 percent or more of their body weight, compared with 20 percent of those who did not feel judged and talked with their doctor about shedding pounds, the findings showed.
The researchers also found that 9 percent of those who felt judged but did not discuss weight loss with their doctor lost more than 10 percent of their body weight, compared with 6 percent of those who didn't feel judged and did not talk with their doctor about weight loss.
Just two-thirds of the respondents said their doctors brought up the issue of weight loss, according to the study published online this week in the journal Preventive Medicine.
The findings suggest that primary care doctors need to avoid negative attitudes about overweight and obese patients, the researchers said.
Some doctors may need to be taught how to talk to overweight and obese patients in a way that makes them feel understood and supported, according to Gudzune. It's best to start with modest goals, such as a 10 percent decrease in weight, she noted.
"We don't want to overwhelm them," she added. "If we are their advocates in this process -- and not their critics -- we can really help patients to be healthier through weight loss."
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases explains how to select a safe and successful weight-loss program.