Last month, Harriet Brown published an article on Slate comprehensively laying out the science around weight loss and showing how (a) diets don’t work long-term; (b) weight loss isn’t healthy; and (c) that it’s out culture’s obsession with being thin that drives people (including doctors) to assume that being thin is healthier than being fat. The Slate article was a summary of what’s in her book Body of Truth, and reflects what fat activists have been saying for years.
In response, Julia Belluz published an article on Vox claiming that Brown’s article was misleading and that losing weight is a worthwhile and attainable goal. Belluz’s article is terrible. It’s so terrible that I have to rant about it at length here. So consider this your trigger warning for angry ranting and diet talk.
Claim One: Diets Don’t Turn Fat People Into Thin People
Brown lays out what we know about diets:
doctors know the holy trinity of obesity treatments—diet, exercise, and medication—don’t work. They know yo-yo dieting is linked to heart disease, insulin resistance, higher blood pressure, inflammation, and, ironically, long-term weight gain. Still, they push the same ineffective treatments, insisting they’ll make you not just thinner but healthier.
In reality, 97 percent of dieters regain everything they lost and then some within three years. Obesity research fails to reflect this truth because it rarely follows people for more than 18 months. This makes most weight-loss studies disingenuous at best and downright deceptive at worst.
Brown’s statements reflect scientific findings about the ineffectiveness of diets over the long-term, which more often lead to weight gain than weight loss (83% in the linked study). Nobody quite knows why that’s happening, but one of the most plausible theories is set point theory, which is the idea that each body has a certain level of fat that it wants, and without drastic interventions, it will remain at the same level long-term. Set points can change, but nobody really knows how, and most diets tend to slightly raise a person’s set point rather than lower it. Set Point Theory applies to fat people and thin people alike:
Kolata goes on to discuss a later study that demonstrated it was just as hard to gain a significant amount of weight and keep it on. Male prisoners agreed to do this weight-gain experiment, and it turned out they had to eat a ridiculous amount of food–literally up to 10,000 calories a day–to increase their weight by 20-25 percent. Once they did that, their metabolisms went apeshit trying to get them back down to their normal weights. As soon as the study was over, the weight fell off.
There is also some evidence that gut microbes contribute in a significant way to weight gain or loss. The thing about all of the theories, though, is that they are not yet proven, and more importantly, that nobody understand them well enough to say how to turn a fat person into a thin person (or vice versa).
Some of the best research on what works for weight loss comes from the National Weight Control Registry, a study that has parsed the traits, habits, and behaviors of adults who have lost at least 30 pounds and kept it off for a minimum of one year.
“What makes maintaining weight loss seem ‘almost impossible,'” writes obesity doctor Yoni Freedhoff, “are the goal posts society has generally set to measure success.” So no to quick diets, yes to long-term lifestyle changes. They can help.
Can you spot the error? I can! A few of them in fact! But the most glaring error is the one-year time requirement. There is no question that people on diets can lose weight and keep it off for one year, maybe even two. But once you get to year three, and especially when you get to year five, nearly everyone has not only regained the weight that they lost, but put on additional weight.
The other error is what’s known as selection bias. The registry includes 10,000 people who have successfully kept their weight off. Belluz tries to use the registry as evidence that long-term weight loss is possible for most people. However, nobody has argued that weight loss is impossible for anyone, just that it doesn’t work for 97% of those who try. Given that 45 million Americans diet every year, that’s over a million people every year who are successful. The existence of a registry of 10,000 people who have successfully lost weight proves nothing other than that they are part of the lucky 3% whose metabolism is cooperative.
Belluz tries to claim that the people on the registry have valuable advice for the rest of us. I’m reminded of a parable about mutual fund management I was told in finance class. Let’s pretend that picking stocks at random will outperform an index fund 30% of the time (the actual number is probably much higher). Let’s also say that there are ten thousand asset managers in the market. That means that, statistically, there will be 24 managers who are able to say “I beat the market every year for the past five years!” They will claim that their success is due to their incredible skills and insights, and try to convince you to invest all of your money with them. Their success is actually due to dumb luck. Their stock picks for the current year are no better or worse than anyone else’s.
The same goes for people who have successfully lost weight. Yes, they exist. No, they don’t have anything to teach the rest of us. For some reason, they got lucky. However, as the vast majority of studies have found, their success is not replicable for most people. They are not role models, and they have no helpful advice for how to turn fat people into thin people. Yes, this includes you.
Claim Two: Losing Weight Doesn’t Improve Health
Brown’s article claims:
Studies from the Centers for Disease Control and Prevention repeatedly find the lowest mortality rates among people whose body mass index puts them in the “overweight” and “mildly obese” categories. And recent research suggests that losing weight doesn’t actually improve health biomarkers such as blood pressure, fasting glucose, or triglyceride levels for most people.
Brown’s claims have been well-documented by various sources. There is an effect some call “the obesity paradox” where “[o]bese patients with heart disease, heart failure, diabetes, kidney disease, pneumonia, and many other chronic diseases fare better and live longer than those of normal weight.”
Belluz takes issue:
Stokes actually looked at more than 10 years of data from the Centers for Disease Control and Prevention and death records of American adults between the ages of 50 and 84, and went back in time, accounting for people’s weight histories. This made it possible to break up the normal weight category into two separate groups that are usually lumped together: those who had maintained a normal weight throughout their lives, and those who were normal weight at the time of the study but had experienced weight loss.
Stokes found that people who were always normal weight had an extremely low risk of death, but that the other normal weight group — with people who were formerly obese — had a much higher mortality rate. After redefining the normal weight category to only include the stable weight individuals, he found much stronger associations between excess weight and mortality.
Belluz claims that this “definitely has implications for the intensity with which we should be pursuing lifestyle and behavioral modification.”
This was the point at which my jaw dropped. I’m still having trouble believing Belluz is serious. She just presented a study that shows that losing weight not only doesn’t make you healthier, but it makes you so unhealthy that it throws off the statistics for the rest of the group, and she uses that as an argument in favor of weight loss! Belluz discovered really good evidence against the idea that weight loss is good for you and then wrote an entire article about how we should all be dieting! And claiming that it will improve our health! I feel like I’m in the Twilight Zone.
Related to the health question, Brown addresses the kind of energy is takes to maintain weight loss long term:
Debra Sapp-Yarwood, a fiftysomething from Kansas City, Missouri, who’s studying to be a hospital chaplain, is one of the three percenters, the select few who have lost a chunk of weight and kept it off. She dropped 55 pounds 11 years ago, and maintains her new weight with a diet and exercise routine most people would find unsustainable: She eats 1,800 calories a day—no more than 200 in carbs—and has learned to put up with what she describes as “intrusive thoughts and food preoccupations.” She used to run for an hour a day, but after foot surgery she switched to her current routine: a 50-minute exercise video performed at twice the speed of the instructor, while wearing ankle weights and a weighted vest that add between 25 or 30 pounds to her small frame.
“Maintaining weight loss is not a lifestyle,” she says. “It’s a job.” It’s a job that requires not just time, self-discipline, and energy—it also takes up a lot of mental real estate. People who maintain weight loss over the long term typically make it their top priority in life. Which is not always possible. Or desirable.
Belluz is unsympathetic:
But I would ask Brown: does being obese require any less mental energy?
Is it really more mentally freeing to feel tired when you walk up a flight of stairs, to have to buy two seats on an airplane because one won’t do, to not be able to play with your children because you’re too unfit, to continually worry about whether your clothes are going to fit in the morning … the list goes on.
This is where Belluz reveals what is at the root of her science-denialism and wrongheaded thinking: prejudice against fatties. Belluz assumes that being fat means you’re too “unfit” to walk up stairs or play with children? That you have to worry whether your clothes will fit? Seriously? In the same way that body size doesn’t determine health, body size does not determine fitness. Newsflash, asshole: fat people exercise! And when a fat person exercises, their muscles, lungs, and heart develop strength and endurance. Just like a thin person! Being fat doesn’t mean it’s tiring to walk up a flight of stairs. There are many fat and thin people alike who end up out of breath after walking up the stairs. There are also many fat and thin people who have no trouble walking up a flight of stairs. Body size does not determine cardiovascular health, and to suggest it does is nothing short of bigotry.
Do you know what actually uses up a lot of mental energy in fat people? Fat stigma, which is exacerbated by ignorant articles pushing tired bullshit that’s been disproven over and over again. Want to improve the health of fatties? Spread the word about Fat Acceptance and Health at Every Size.
I am fat. I have always been fat. I am actually one of the lucky few who has managed to lose weight and keep it off long-term, which I did almost a decade ago by starting low-carb and then going low-calorie. Since then, my weight has been slowly but surely creeping back up. I’ve tried low-carb followed by low-calorie again, with no effect. I’ve tried going low-carb for longer. No effect. I’ve tried Whole30. No effect. I’ve tried The Smarter Science of Slim. No effect.
I’m not doing it anymore. I live a healthy lifestyle. I drink green smoothies for breakfast. I eat salad for lunch. I probably eat fewer calories than you do. I exercise regularly. I’ve started jogging. I walk up three flights of stairs to my office no problem. My doctors tell me I’m in excellent health. I have no reason to lose weight, and I’m not going to.
If Julia Belluz has a problem with that, she can kiss my fat ass.