Okay, I’m not super wild about the title–not because I think fatness is bad, but because I think it plays into our cultural view of fat as a pejorative–and the book could use a little more intersectionality (though there is some), but otherwise, I highly, highly recommend it. It’s thoroughly researched, rigorously cited, and presents mountains of evidence I was unfamiliar with that have completely convinced me that calories in/calories out is laughably simplistic, that long-term weight loss is like a unicorn, and that the best things we can do for ourselves is find movement we like, eat nourishing foods, and not restrict.
All things I knew and agreed with politically, but had lingering “but what about”s that would pop up and fuck with my brain.
The short version is that we all have a defended range (like set-point theory, but a range) that likes to get higher but almost never gets lower (likely because pre-agriculture a defended range that lowered in response to food scarcity would be a death sentence). The number of factors that impact our defended range is mind-blowing and includes things that are never, ever talked about in mainstream discussions of weight and health. Factors including gut biome, history of dieting (diets almost always raise your defended range, leaving you permanently heavier than at the start), antibiotic use in early childhood, pre-natal conditions, famine in your grandparents’ generation (this one just blows my mind!), poverty, stress, weight-related stigma and abuse, racism, childhood abuse, and on and on and on. This is just a small number of the factors that impact defended range, but even if these were all of them, they so clearly show the folly of religious adherence to “calories in<calories out.” Especially when people inevitably start getting on their (im)moral high horse about it.
If you’re looking for another nail in the coffin of calories in/calories out, she talks about a twin study that measured total daily energy expenditure and carefully calibrated caloric intake so that all of the twins (all male) were at a 1000 calorie deficit. Now, you’d expect sizeable changes in weight based on a 1000 calorie deficit, and some had that. Some sets of twins lost 26 pounds each. Other sets on that 1000 calorie deficit? 2 pounds. Over a span of, I believe, four months. Remember, this deficit was calculated for each person to ensure it was an actual deficit. But some bodies respond to immense restriction (and 1000 calories a day is immense restriction) by refusing to budge, because they are already near or at the bottom of their defended range and their body has a whole host of biological processes that prevent weight loss.
It’s also remarkable for the times she talks to doctors about the success rate of the weight loss advice they give (about a 5% success rate–incidentally the same success rate as AA*). They agree that they wouldn’t prescribe a medication with a 5% success rate and high probability of negative side effects, and yet say they won’t stop giving patients advice they know doesn’t work because they “have to do something.”
Since reading this book I feel like I’m seeing the world with fresh eyes. While I have, for a long time, supported body acceptance and choosing healthy habits for the sake of health rather than weight loss, seeing the weight of evidence supporting this approach has made me utterly intolerant of weight loss talk, sanctimonious appeals to calories in/calories out, and the general state of Western society when it comes to bodies, nutrition, exercise, weight, and health. I highly, highly recommend this book to one and all.
*I note this both because that was my immediate thought when I saw the statistic and because I find the devotion and moralizing around both fascinating–especially given their exceptionally high “failure” rates.