Fatphobia, says philosopher Kate Manne, has become a vital social justice issue. In her new book, “Unshrinking: How to Face Fatphobia,” Manne draws on personal experience as well as scientific research. Fatphobia is a social system that unfairly ranks bodies according to thinness, “in terms of not only our health but also our moral, sexual and intellectual status,” writes Manne, associate professor of philosophy in the College of Arts and Sciences.

After her widely cited first book was published – “Down Girl: The Logic of Misogyny” – Manne was often asked to explain her interest in misogyny. That answer led to “Unshrinking,” which includes descriptions of her childhood experience at a boys’ school, where misogyny took the form of fatphobic attacks on her body.

Manne spoke with the Chronicle about the book.

Question: In addition to describing the intersection of fatphobia with misogyny, you also connect it with anti-Black racism. Can you explain?

Answer: Fatphobia is a historically recent systemic form of prejudice. In the past, fatness was often celebrated and seen as a sign of wealth and luxury and prosperity. As the sociologist Sabrina Strings has shown, it was in the mid-18th century that anti-fatness was born out of a need to differentiate white bodies in France and Britain from the Black bodies who were being so brutally enslaved. It’s not that fatness was first derogated, and then Black bodies were associated with fatness. It went the other way. Fat bodies and Black bodies were associated, and that was used to impugn fat bodies and fat Black bodies specifically shortly thereafter. That history is important to grapple with, both to see how contingent and historically recent fatphobia in its systemic form is, and also to see that it is really a powerful tool of anti-Black racism even today.

Q: Fatphobia is often justified by health concerns; why do you contend instead that “it is fitness, not fatness, that matters most”?

A: The message of this book is basically that dieting is a really bad idea. And unfortunately for me, because I happen to hate exercise, exercise is a really good idea. We see many promising longitudinal studies of people who were really fit even if they were also fat, and who have excellent health outcomes on average.

With dieting, people can lose a moderate amount of weight initially, but the weight comes back pretty inexorably over a five-year period, and, in fact, between one- and two-thirds of people will end up heavier than when they started. The health ill effects of going up and down in weight are really significant, so independently of what you actually weigh, weight cycling – that is, losing and regaining and losing and regaining weight repeatedly – turns out to be harmful for our health across a bunch of measures like cardiovascular health, immune function, metabolic function (including the risk of Type 2 diabetes), and also mental health.

There is a correlation between being very heavy and not being as healthy in certain ways, but that is often just as explainable by the fact that these people aren’t getting adequate health care and are being subjected to the stress of stigma and/or weight cycling.

Q: Can you explain what you mean when you say that fatness is a moral issue?

A: It’s often framed as a moral issue that people should feel guilty or ashamed for being fat, and what I’m trying to say in the book is that there’s just nothing morally wrong with being a fat person and part of that is because fatness is mostly unchosen. There is this long-standing myth that we’re in pretty tight control of our body size and shape, and that just turns out not to be true. Upwards of 70% of the variation in the human population that we find in terms of body mass is due to genetics, which makes it just a little bit less heritable than height.

It’s not immoral to fail to do something that’s practically impossible in the long term for the vast majority of people or could only be done through measures that are unreasonable to demand of people – like taking the new class of weight loss drugs and things like bariatric surgery that can have prohibitive costs and side effects.

Q: In your conclusion, you advocate for “body reflexivity.” What do you mean by this, and why is it a political statement?

A: The idea that I call body reflexivity says: My body is for me. Your body is for you. Your perspective on your own body is the only one that matters, and our bodies are just not there for serving or pleasing or placating others. It’s about throwing out the idea of assigning any sort of fixed value to bodies whatsoever, and instead regarding our bodies as our homes – and as something that we should have full control over. This is connected with a radical politics of autonomy that would vindicate the right to be queer, to be trans, to be fat, to be old, to be disabled, to be any number of derogated social categories in the way that we move through the world in our embodiment, and to be unapologetic and proud of it.

Linda B. Glaser is news and media relations manager for the College of Arts and Sciences.