Obviously, re: the Obesity Epidemic (BOOGA-BOOGA OMG DEATHFAT), which I'm sure you've heard about, and probably spend a great deal of time worrying about for yourself or some Poor Fat Person you know, a great many doctors DO have biases against fat people.
2009 October 8, firefey [username], “Re: Obama with Goths”, in alt.gothic[1] (Usenet):
it's made of people you probably see everyday[sic] and don't even think are fat, let alone deathfat.
2012, Lesley Kinzel, Two Whole Cakes: How to Stop Dieting and Learn to Love Your Body, unnumbered page:
To put it more succinctly, I am death fat. I am superduper really-for-real mad fat. I am the kind of fat where doctors are friendly until they get me on a scale, and then after that they get very quiet.
2012, Lonie McMichael, Ph.D., Talking Fat: Health vs. Persuasion in the War on Our Bodies, unnumbered page:
Of course most fat individuals want to be slimmer. When I tell them they have very little chance of ever being slim, I am telling them that, with our society as it is, they will always be socially unacceptable. For larger individuals—what the Fatosphere jokingly refers to as “deathfat” as a play on the term “morbidly obese”— leaving their homes opens them to criticism and ridicule […]
2014, Kala Heekin, "Fat Babes In Crop Tops: Representations Of Gender In Fa(t)shion", Society & Culture Undergraduate Research Forum, Volume 6, Spring 2014, page 148:
Death fat individuals may find that smaller fat people are taking up more space in fa(t)shion and are more commonly seen in these blogs.
2015, Barbara Altman Bruno, "Heath at Every Size and me", Fat Studies: An Interdisciplinary Journal of Body Weight and Society, Volume 4, Issue 1 (2015), page 11:
As of 2010, there were more than 100 blogs and other online resources for people who refused being linked to what one of those bloggers referred to as “deathfat” (Kinzel, 2009).
Noun: "(slang, sarcastic) a morbidly obese person"[edit]
2013, Caroline Narby & Katherine Phelps, "As Big as a House: Representations of the Extremely Fat Woman and the Home", Fat Studies: An Interdisciplinary Journal of Body Weight and Society, Volume 2, Issue 2 (2013), page 157:
This signification is reflected in the medical term “morbid obesity,” and fat activists who might be considered “morbidly obese” by the medical establishment sometimes refer to themselves as “death fats.”
2013, Maya Maor, "More: Fat Women in Israel-Genres and Issues in Identity Construction and Resistance to Social Oppression", thesis submitted to Ben-Gurion University of the Negev, page 104:
Some US fat activists distinguish between ‘inbetweenies,’ who are relatively ‘small’ fat people who enjoy privileges such as ‘passing’ as thin or ‘on their way to being’ thin, and ‘death fats,’ who suffer the worst of the sanctions society places on fat people (McMichael, 2010).
2016, Laura Ellen Joyce, "Flesh Home: The Uncanny Female Architecture of Blake Butler's EVER", in Fat Sex: New Directions in Theory and Activism (eds. Helen Hester & Caroline Walters), unnumbered page:
The protagonist is aligned to the abject in this room as she wears her dress of rot but she is also aligned to the "death fats" and she exists at a great distance from the slender angels above.
"Even within the international fatosphere and rad places of the internet, a lot of the fat femme people have perfectly chiseled faces. Even the deathfats," Rodríguez later tells me in an interview.