21/06/2024

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Where are the missing bodies in that new WeightWatchers study?

Where are the missing bodies in that new WeightWatchers study?

I wish that science was always perfectly…scientific…but sadly, it’s not. Case in point: the abstract of a new WeightWatchers study published in the journal Obesity says that of 2,843 weight loss maintainers in WeightWatchers who were followed for one year, 57% continued to maintain their loss while 43% gained more than five pounds. That sounds not too bad, right? Let’s put a pin in that, while I remind you to never, ever just read the abstract. Especially in the case of this study, where a lot of bodies that went missing.

For this study, the researchers tapped participants in the WeightWatchers Success Registry (sort of a version of the National Weight Control Registry, which I was a part of when I was eyeballs deep in diet culture and had a deeply disordered relationship with food and movement). Specifically, they tapped 7,025 participants aged 18 years or older who had reported at least one year prior that they had lost at least 20 pounds through Weight Watchers.

7,025? What happened to the 2,843 number? Where did those extra 4,182 people go? How did 60% of the original group, or 6 out of 10 people, go poof?

OK, they didn’t all go poof. Only 4,004 (57%) of them went poof, by never filling out a questionnaire at the one-year mark. (Data from an additional 30 people was removed because it was “implausible,” while data from 148 people was removed because they lost more than five pounds during the year of follow-up, which could have been due to other factors, such as illness.)

So of the 2,843 people left 1,632 maintained their Weight Watchers weight loss within five pounds either way (average gain less than one pound), while 1,211 gained more than five pounds during that year (average gain about seven pounds). As I said at the beginning of this post, on the surface that looks not terrible shabby…but what about those missing bodies?

Helloooooo…where did you go?

Why might those 4,004 people have opted not to fill out the questionnaire despite being part of the “success registry”? Could it be because they had regained weight and were ashamed? An educated guess tells us that’s a likely scenario, although obviously we have no way of knowing that for sure.

Some of those 4,004 people may have been too busy to fill out the questionnaire. The reminder email may have landed in their spam folder. Some could have died. Who knows.

But riddle me this: if you lost weight and kept it off (a scenario that is highly celebrated in our weight-obsessed society), wouldn’t you be likely to share and celebrate that fact? Wouldn’t you be proud to participate in research that shows that it IS possible to lose weight and keep it off?

I know I was super proud to join the National Weight Control Registry, thrilled to fill out the super tedious annual questionnaires (how exactly are you supposed to estimate your average weekly peach intake when you eat them a few times a week for a few months per year while they are in season?).

Or, I was thrilled until the inevitable weight regain began, despite the fact that I was still obsessively monitoring my food and movement. Then I stopped filling out the annual surveys, and eventually they stopped sending them (I have a sneaky suspicion that I still exist in their database as a weight loss “success” story, because I never gave them data that showed otherwise).

Anyway, I feel confident that it’s safe to say that in this study, and in other weight loss studies where a significant percentage of participants are “lost to follow up” that weight gain is the reason most of them went MIA.

They say failure, I say self-preservation

That was the part of the study that made me do math. Now let’s talk about the part of this study that pissed me off.

The authors said there were a number of changes over the year of the study that may have separated the gainers from the maintainers. Specifically…

Them: “…gainers demonstrated declines in the practice of evidence-based weight-control behaviors measured by the WCSS, including self-monitoring, physical activity strategies, and dietary choices and coping. Gainers also reported increases in initiating [eating in the absence of hunger] and declines in habit strength for healthy eating and activity.”

Me: O-kaaaay, so the gainers snapped in the face of ongoing restrictive food and exercise behaviors, and decided that if they had to record One More Bite And One More Step they were going to spontaneously combust. That sounds like self-preservation. Also, eating in the absence of hunger is a totally predictable response to dieting. It’s the “binge” part of the restrict-binge cycle

Them: “Relative to maintainers, gainers reported greater increases in disinhibition (i.e., loss-of-control overeating in response to external and internal stimuli) and willingness to ignore food cravings. Gainers reported increases in self-judgment and isolation and worsening body image, perceptions of general health, mental health, and bodily pain.”

Me: Again, binge-restrict cycle. This is a logical response to real or perceived deprivation, and if you’re dieting, that deprivation may include food choice, food amount (aka, you’re starving yourself) and being tired of skipping social events because you need to exercise or are afraid of being around food you “can’t eat.” As for the self-judgment, isolation and all the rest of that sentence? Well, duh.

When you feel like you’ve “failed” at yet another diet, and you’re gaining weight, you will probably judge yourself. You’ll probably also worry that you’re ruining your health (because we’re all told that weight = health, even though it doesn’t). If you’re isolating yourself, your mental health is going to take a hit, and if you are hiding and feel too self-conscious to go for a walk or go to your yoga class, then your body is probably going to hurt.

Oh, and one more thing

I would be remiss if I didn’t acknowledge the elephant in the room: the data collected in this WeightWatchers study is self-reported and self-reported data is notoriously not reliable.

Am I saying that these study participants are liars? No, not really. But given that…

…we have a very human tendency to want to be successful, and…

…many people are people-pleasers, and…

…there is a perceived researcher-participant power differential that may elevate any people-pleasing tendencies, and…

…the last thing you want to do when dieting is “fail” by regaining weight…

…then there’s a very good bet that some/many of the “maintainers” fudged their numbers a bit.

I did that when I was still part of the National Weight Control Registry, because I persuaded myself that I would “correct” the weight gain before the next annual survey came around. When it eventually became clear that was not going to happen despite my best efforts, I stopped filling out the surveys.

So, let’s look again at the assertion that 57% of people in the WeightWatchers Success Registry maintained their weight over one year of follow-up, and 43% experienced weight regain of more than five pounds.

If you factor in the 4,004 missing people, and assume that they went MIA because they gained weight, then 23.1% maintained their weight and 72.9% experienced weight regain. Now, OK, some of those 4,004 probably were just too busy to respond at the end of the year, and maybe they did maintain their weight…but I bet that was offset by the “maintainers” who did respond, but didn’t reveal that they actually gained weight.

A silver lining…or is it?

I was tickled by this statement from the WeightWatchers study authors: “Despite regaining weight, gainers’ weight remained 18% below their WW starting weight, exceeding weight-loss maintenance criteria for long-term successful weight loss and supporting other research in the field.”

OK, not tickled. More like annoyed. This is one of the sneaky, trickster-like nuggets that is present in almost every weight loss study. Even though some/all of the participants are actively regaining weight, the authors say something celebratory about them still being below their starting weight. As if time stops when the researchers stop following up.

No, what actually happens is weight is on an upward trajectory, and it will likely continue on that path. We don’t know where or when the regain will stop. Maybe some participants won’t regain ALL their lost weight, but some will certainly regain MORE. And because of a phenomenon called “fat overshooting,” all the regainers will probably end up with more body fat and less muscle than they started with.

This is why going into a “calorie deficit” (aka starvation) in the intentional pursuit of weight loss is a losing proposition. And it’s the fault of diet culture, the commercial diet industry, and the medical weight loss industry. It is NOT the dieter’s fault!

And I make sure I let my clients who have been harmed by WW (whether it triggered an eating disorder or simply, and frustratingly, left them unable to look at food anymore without thinking about points) that’s it’s not their fault. They were just doing what they thought they were supposed to do.


Carrie Dennett, MPH, RDN, is a Pacific Northwest-based registered dietitian nutritionist, freelance writer, intuitive eating counselor, author, and speaker. Her superpowers include busting nutrition myths and empowering women to feel better in their bodies and make food choices that support pleasure, nutrition and health. This post is for informational purposes only and does not constitute individualized nutrition or medical advice.

Seeking 1-on-1 nutrition counseling? Carrie offers a 6-month Food & Body program (intuitive eating, body image, mindfulness, self-compassion) and a 4-month IBS management program (low-FODMAP diet coaching with an emphasis on increasing food freedom). Visit the links to learn more and book a free intro call to see if the program is a good fit, and if we’re a good fit!

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