But the full-figured African-American nominee is also under fire for being overweight in a nation where 34 percent of all Americans aged 20 and over are obese.
Critics and supporters across the blogsphere have commented on photos of Benjamin's round cheeks, saying she sends the wrong message as the public face of America's health initiatives.
But others support the 52-year-old founder and CEO of Bayou La Batre Rural Health Clinic, citing new research that shows you cannot always judge a book by its cover when it comes to obesity.
Even the National Association to Advance Fat Acceptance -- whose slogan is "we come in all sizes" -- has jumped to her defense.
"The job of surgeon general is to make health care and policy decisions for the country -- not to look hot in a pair of skinny jeans," said one blogger on Frisky.com. "Perhaps her size could actually be an advantage -- she's in a better position to understand obesity and contemplate out-of-the-box ways to roll back ever-expanding American waistlines."
Bloggers on Salon.com speculated that Benjamin is 40 pounds overweight, perhaps a size 18. The nominee didn't return calls from ABCNews.com, so there is no information about how much she weighs or her eating and exercise habits.
Spokesman for the Department of Health and Human Services Jenny Backus issued this statement: "Dr. Benjamin is a highly qualified physician who has dedicated her life to providing care to her patients. She is a role model for all of us, and will be an outstanding surgeon general."
Even some of the most reputable names in medicine chimed in.
"I think it is an issue, but then the president is said to still smoke cigarettes," said Dr. Marcia Angell, former editor of The New England Journal of Medicine who is now a senior lecturer at Harvard University Medical School. "It tends to undermine her credibility."
"We don't know how much she weighs and just looking at her I would not say she is grotesquely obese or even overweight enough to affect her health," Angell told ABCNews.com.
"But I do think at a time when a lot of public health concern is about the national epidemic of obesity, having a surgeon general who is noticeably overweight raises questions in people's minds," she added.
The potential for hypocrisy bothered others.
"When a teenager listens to this person I want them to listen and respond in a positive way," said Lillie Shockney, administrative director of the Johns Hopkins Avon Foundation Breast Center. "Not say ho-hum and then drive to a fast food place."
The controversy swirled on the Internet just as the Centers for Disease Control and Prevention plans its end-of-month "Weight of the Nation" forum to address strategies to deal with the obesity epidemic.
During the past 20 years obesity has dramatically increased in the United States and is considered a major health risk for cardiovascular disease, diabetes and cancer, costing the nation billions of dollars a year in health care costs.
In 2008, only one state, Colorado, had an obesity rate of less than 20 percent. In states like Alabama, Mississippi, Oklahoma, South Carolina, Tennessee and West Virginia, the prevalence is greater than 30 percent.
Dr. Sarah Lester, a pediatrician from Andover, N.H., told ABCNews.com she lost 30 pounds, setting a good example for her patients' families.
"I do think it makes a big difference," said the 38-year-old. "Many ask me how I did it and when I tell them more exercise and eating less many are disappointed. However when they hear even for me there isn't a magic bullet, I think it helps."
New CDC data show that compared with whites, African Americans have a 51 percent higher prevalence of obesity and Hispanics have 21 percent higher obesity prevalence.
Some say that as an African American, Benjamin could set a better example.
"It is important to 'walk the walk and not just talk the talk,'" said James Anderson, a professor of medicine and clinical nutrition at University of Kentucky Medical Center. "Oprah struggles as a role model and has given up, as I understand it. Rumor has it that President Obama still smokes. We need role models who are attempting to be leaders for change in health and lifestyle to be role models."
But other top health professionals argue that one can be fit and fat.
"I thank God that Dr. Regina Benjamin is a fat woman," said Joanne Ikeda, a nutrition specialist at the University of California, Berkeley. "Maybe now we will stop making the assumption that all fat people are unhealthy particularly in light of new data coming from the National Health and Nutrition Examination Survey."
Data from that survey show that more than half of so-called overweight people are metabolically healthy, compared to one-quarter or about 16.3 million adults 20 years or older, who are "metabolically abnormal."
The study emphasizes looking at a person's metabolic health -- blood pressure, cholesterol, inflammation and sugar level indicators -- as a better diagnostic tool for future health problems.
"I am appalled that this amount of bias and discrimination exist regarding large people," said Steven Blair, professor of exercise science at Arnold School of Public Health, University of South Carolina. "The focus should be on Dr. Benjamin's credentials and accomplishments. What difference does her size make?"
The former CEO of the Cooper Institute agreed that it is impossible to determine from a photo whether someone is eating a healthy diet or exercising regularly, the cornerstones of physical fitness.
"I cannot resist stating that although too many people assign all sorts of bad traits to overweight/obese people, from being lazy, poor workers, I can think of some pretty bad characters who are thin," he said.
Blair, who told ABCNews.com that he is also overweight, said "even people who are obese are themselves biased."
That negative stereotype even colors national research, which puts an emphasis on caloric intake rather than energy expenditure, according to Blair.
"Should the face of public health practice a healthy lifestyle?" he asked. "Yes, she should not smoke or engage in other unhealthy behaviors and not exercise. I have been harping on this for the last 10 to 15 years. Let's focus on healthful behaviors instead of the way they look."
But Dr. Otis Brawley, chief medical officer for the American Cancer Society, and an African American, said there may be "some discrimination people don't realize."
"Obesity has a huge environmental component and is rooted in how one is fed in childhood and what physical activities you partake in the inner city," he told ABCNews.com.
"Poverty is conducive to obesity," said Brawley. "I think Dr. Benjamin may understand the root causes and effectively address the problems more than skinny people."
Dr. Susan Love, president of the eponymous research foundation, said Benjamin was attacked because she was a woman, reminding that the former surgeon general C. Everett Koop was "no string bean."
"Now I do suspect some of the questioning is a sexist thing in that as a society we still promote the thin, trim female -- a fact that might be a contributor to our problems with eating disorders," said Connie Diekman, a registered nurse and director of university nutrition at Washington University in St. Louis, Mo.
Patients also came to her defense.
"Doctors are human, too," said Chris Hill, a 51-year-old "overweight" pharmacist from El Paso, Texas. "They get sick, smoke, overeat and die like everyone else. Everyone does not have to look like a TV anchor in order to do a good job etc. Being healthy and tiny are not the same things. Are you saying overweight people can't or shouldn't be professionals?"
"My primary care doctor was overweight and was always telling me I needed to lose a few pounds," said Adeeba Deterville, a 47-year-old consultant from Oakland, Calif.
"I did feel it was odd for her to be advising me, when she needed to do it herself. However, I also found some comfort in knowing that she was struggling too and that helped me feel "not preached to. I knew she could relate."
Dr. Clyde Yancy, president of the American Heart Association, said he was "incredulous" at the criticism.
"For the surgeon general to fulfill her responsibility goes beyond anything such as a physical metric," he told ABCNews.com. "What we need are health care leaders who are qualified, passionate, results-oriented and part of a team for the great good. She is all that."