Review: Secrets from the Eating Lab

I first became interested in this book after reading an interview with author Traci Mann from shortly before the book came out. If her name seems familiar, you may recognize it from a study that is often cited in fatosphere blogs, Medicare’s search for obesity treatments: diets are not the answer [article/press release about the study]. This is a relatively short, readable book, with occasional flashes of humor, which despite its brevity is a fairly comprehensive look at the science around weight loss and gain, set points, and the psychology behind eating. However, despite its strong critique of diets and the weight loss industry, and its skeptical stance towards the importance of BMI, it is not 100% weight neutral because it recommends staying at the low end of your set point range, so readers for whom any pro-weight-manipulation talk is problematic should proceed with caution.

The first chapter, “Diets Don’t Work”, deals with the evidence showing that diets don’t work, and looks at not just how few long-term diet studies show permanent weight, but also how few dieters reach their goal weight, why “successful” weight loss has been repeatedly redefined as a smaller reduction in weight, and all the reasons why the conditions of the studies lead to the results looking better than they are.

The second chapter, “Why Diets Don’t Work: Biology, Stress, and Forbidden Fruit”, discusses set points, biological and psychological factors that lead to weight regain, and the effect of stress on weight. And, importantly, that calorie restriction causes a stress response, so the very act of restricting calories makes it harder to restrict  calories. (She also describes how they separated out the potential stress of monitoring your food from the potential stress of not eating as much food–calorie restriction was stressful even when those being restricted were not responsible for tracking their food [because all of their food was provided by the researchers].)

With some of the biological responses that Mann treats as separate things, I wonder how much they’re different manifestations of the same thing–for example, dieting causes ghrelin to go up and leptin to go down, and also causes changes in brain activity that make you more likely to notice and pay attention to food, and to find it more appealing than normal. Could those changes in brain activity be in response to changes in hormones such as ghrelin and leptin?

One thing that I didn’t think of until after finishing the book that Mann didn’t address was how and whether set points can change. I know I have seen talk people say that dieting can, for some people, ratchet up people’s set points, and other people seem to have higher set points after going through pregnancy–I’m not sure if there have been any studies of that, though, and without studies Mann might not want to include it.

In chapter 3, “The Myth of Willpower”, Mann looks at why willpower is not, contrary to popular belief, a major factor in most people’s weight. (Take that, Geoffrey Miller!) While I already knew that set points and other factors made it so that not everyone has to put in the same amount of effort to weigh a certain amount, and it seems obvious that not everyone will put weight loss/maintenance at the top of their Willpower Priority List, one thing I didn’t know was just how little correlation there is between eating behavior and willpower. Here Mann talks about some evidence that is particularly convincing to me:

In one of the studies, psychologists Malte Friese and Wilhelm Hofmann asked participants to try to resist some potato chips, and then they looked at whether subjects who got high scores for self-control on the questionnaire had been better able to resist the potato chips than the subjects who scored low. They hadn’t. When it came to resisting highly tempting food, it turned out that self-control ability didn’t matter much.

But it’s not that self-control has no impact at all on human behavior. On the contrary. A few years after we completed this research [looking for studies that both used self-control questionnaires and had participants do an exercise that required self-control] another set of researchers tracked down more self-control studies and examined how well self-control ability correlated with the inhibition of various types of behavior. When it came to things like schoolwork, grades, and even happiness and depression, self-control played a major role. Eating, however, was far less influenced by self-control ability than any other type of behavior they studied. In fact, self-control mattered only half as much for eating as it did for other behaviors.

In chapter 4, “Diets Are Bad for You”, Mann talks about the negative effects of dieting. Here she goes into one of those negative effects:

Focusing extensively on food and eating (and sometimes also concerns about your weight) steals valuable attention from other activities, and the more preoccupying food thoughts dieters have, the more difficulty they experience thinking about other things and handling other cognitive tasks. It doesn’t take much for a dieter to become preoccupied with thoughts of food. In one study, researchers tested dieters and non-dieters on their memory ability before and after having them eat a chocolate bar. Not surprisingly, dieters had more preoccupying food thoughts after eating the chocolate bar, and their memory function suffered as a result. These kinds of memory and problem-solving deficits may make it difficult for dieters to successfully focus on important daily activities.

Other problems caused by dieting include negative feelings such as shame–which can have physical consequences–stress, and weight cycling. Mann says that “There is no consensus in the medical community on whether weight cycling is unhealthy. Researchers can’t even agree on what constitutes weight cycling,” but concludes, “the majority of the evidence suggests that weight cycling is associated with an increased risk of illness and death.”

In chapter 5, “Obesity is Not a Death Sentence”, Mann talks about Katherine Flegal’s research on BMI and mortality, the “obesity paradox”, and the difficulty of showing causation between obesity and health outcomes. Mann discusses the differences other than weight between thin and fat people on average, including that fat people are more likely to be sedentary than thin people, more likely to have undergone weight cycling, more likely to have low socioeconomic status, are discriminated against in medical care, and experience greater loneliness, stress and stigma. I had always assumed that for something as obvious and with such a strong effect on health as socioeconomic status, researchers would generally control for it as a matter of course. Nope:

There are statistical techniques that can be used to minimize the extent to which these kinds of variables bias study results. They are routinely used to account for age and gender differences, but it is not routine to use them for these other potential forms of bias. I went through the list of ninety-seven studies on obesity and mortality that Katherine Flegal included in her thorough review and counted how many studies controlled for each of these factors. Physical activity was the most likely to be statistically controlled for, but that was done in fewer than half of the studies. Only sixteen of the studies took socioeconomic status into account, one study controlled for distribution of body fat, and none accounted for weight cycling, stigma or stress, or use of diet drugs. No study controlled for more than two of these factors, and half didn’t control for any. When researchers fail to statistically control for these factors in their studies on obesity and health, they make obesity look more dangerous than it is.

(Presumably animal studies would eliminate most of these confounding factors, but those have their own problems.)

Chapters 6-10, “Lessons from a Lean Pig”, “How to Trick Your Friends into Ignoring a Cookie”, “Don’t Call That Apple Healthy”, “Know When to Turn Off Your Brain”, and “How to Comfort an Astronaut”, have a lot of fascinating research in them. They also make up a section of the book called “How to Achieve Your Leanest Livable Weight (No Willpower Required)–it’s basically supposed be about how to stay at the low end of your set point range, though Mann also says, “these strategies will painlessly stabilize your eating and keep your weight from yo-yoing” (which is certainly a plus IMO even if your average weight remains the same). It irked me that (back at the end of chapter 2) Mann said “For all of us, the aim should be to live at the low end of our set range.” (Don’t you ‘should’ at me, Traci Mann!) To be fair, this seemed more aimed at dieters hoping for radical weight loss than anyone else, but she does say ‘everyone’. I mean, if you’re going to focus on weight that seems like the prudent thing to aim for, but I don’t see anything in the book that convinces me that it’s a better approach than focusing on behavior and assuming your ‘healthy weight’ is the weight you’re at when you’re doing healthy things. (You don’t have to be a hardcore HAES advocate to have problems with this section–a hardcore mindful eating advocate [related but not the same] also had problems with it.)

But most of the strategies are aimed at either mindless [not-in-touch-with-your-hunger] eating, or eating more vegetables, and a lot of the strategies she mentions in the ‘Leanest Livable Weight’ section could be repurposed–for example, if you have (pre)diabetes and are managing it in part by limiting carbs, or if you’re trying to eat more in line with the principles of Intuitive Eating or Eating Competence but still struggle with mindless eating of food you don’t even exactly want. Or if you’re trying to eat more vegetables, a lot of advice is specifically about that, so no repurposing is even needed. Some of it is useful outside of eating habits, too–I’m thinking particularly of “implementation intentions”. You could make an implementation intention, for example, of “If my family member starts talking about how the food we’re eating is unhealthy and trying to bond over guilt, then I will say, ‘Let’s just enjoy this.'” And I think this section is also worth reading for the interesting psychological insights–and in particular, a lot of stuff in these chapters reinforces Mann’s argument that weight and willpower have very little to do with each other.

In the final two chapters, “Why to Stop Obsessing and Be Okay with Your Body”, and “The Real Reasons to Exercise and Strategies for Sticking with It”, and “Final Words: Diet Schmiet”, Mann gets back to stuff that’s more in line with mainstream HAES and fat acceptance.

Criticism of the “love your body” maxim is almost as common as uncritical expression of it, but Mann takes one of the less-common routes:

Allow me to suggest a revolutionary action: Let’s try to be okay with our bodies. I am not saying you have to love your body. I can’t help but notice that this goal is frequently pushed on women, but never men, and if men don’t need to love their bodies, it seems to me that women can get by without it, too. For a long time I bought into all the talk about learning to love your body, but I’ve come to think it’s a somewhat misguided goal. Not because it’s impossible (though it’s difficult for most), but because it’s unnecessary. Perhaps loving your body is something to strive for, but all we really need to do is respect our bodies, appreciate them, and be generally okay with them. Body okayness doesn’t mean letting ourselves go, binge eating, or not being physically active. It just means not letting our bodies become our primary life projects.

I hear quite a few people within Fat Acceptance say that they identify/agree more with “love as a verb” for “love your body”, and I would say I’m one of them. I do also see the value in trying to see the beauty in your body, and I’m even reasonably good at that, but I also keep thinking “I can’t wait for my robot body” every time I get tendonitis or plantar fasciitis or some such thing. Even before reading this passage, I was thinking to myself that respecting my body was more what I was going for than loving my body. And as Mann goes on to point out in this chapter, people in the past were more concerned about improving their character than their bodies (or at least, were more likely to talk about that, which sometimes seems like at least as much of an improvement as actually being more concerned about that, especially when I’m listening to one of my coworkers talk about his green smoothies or something).

In Chapter 12, “The Real Reasons to Exercise and Strategies for Sticking with It”, Mann goes over all the reasons to exercise that are not related to its effect on weight (though she also throws in that it helps you get to/stay at your Leanest Livable Weight), and how to overcome some barriers to exercising–not concrete barriers like “my neighborhood isn’t safe to walk in” or “I have a bad hip”, but difficulty getting motivated and exercising as often as you plan to. Many of the strategies are similar to the strategies around food discussed earlier in the book.

In the final couple pages, “Diet Schmiet”, Mann ties it all together, once again says why diets are not just ineffective but harmful, and why you can be healthy without them, that focusing on doing healthy things is the best way to be healthy, that aiming for your Leanest Livable Weight is a sensible goal and does not require willpower, and that you should stop focusing so much on your body anyway.

 

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