Weight Watchers Long-Term Research
Studying the studies
In the last newsletter, I gave a general overview of Weight Watchers (aka WW) and all the tricks they use to sell a program that doesn’t work. Today I’m going to dig into the research. I started at Weight Watcher’s own “Science Center.” They pointed to two studies to back up their claim that “WW is one of the few programs that fulfills all of the criteria that expert panels deem necessary in order for behavioral lifestyle weight-loss interventions to be effective”
First of all, that’s…a lot of words. I’m going to move beyond some questions like - what criteria, and panels of what kind of experts? Instead, I’ll point out that they seem to be taking great care with this phrasing to avoid saying that their program is actually effective. I think that a review of the research will help clarify that choice.
At any rate, the first study they cite is
Extended and standard duration weight-loss programme referrals for adults in primary care (WRAP): a randomised controlled trial
This 2017 study compared three groups of people who were all 18 or older with a BMI of 28 or higher. They looked at three interventions:
1. Brief advice and self-help materials
2. 12 weeks of Weight Watchers
3. 52 weeks of Weight Watchers
They checked in with participants at one and two years. (Of course, most people gain their weight back within five years but we’ll get to that in a moment.)
They started with 1,269 participants, 823 completed the one-year survey, and 856 completed the two-year survey.
At year one
Brief intervention: average loss of 7.19lbs (3.26kg)
12-weeks of Weight Watchers: average loss of 10.47lbs (4.75kg)
52-weeks of Weight Watchers: average loss of 14.9lbs (6.76kg)
So, on average, people in Weight Watchers for 12 weeks lost 3.3 more pounds in a year than the people who didn’t participate in Weight Watchers at all, and the people in the year-long program lost 7.7 pounds more in a year than those who didn’t participate in Weight Watchers and 4.4 pounds more in a year than people who were on the program for 40 fewer weeks than they were.
Ok, before we go further, I feel compelled to remind you that I didn’t cherry-pick this study to make fun of it, it’s literally the first study that WW points to as proof of their efficacy.
The study says “Differences between groups were still significant at 2 years” which seemed oddly nonspecific. Luckily, they included a graph to elucidate:
The graph makes it clear that, in actuality, differences among the groups had collapsed by year two, and everyone was on track to regain all of their weight (a reminder that if a variable is going straight up, the most basic research methods require that we not assume that it will level off the moment we stop tracking it.) And, of course, while everyone is gaining their weight back, Weight Watchers doesn’t refund money spent on program fees, cookbooks, WW-branded food and merchandise etc.
How did the study authors “interpret” these results?
The “interpretation” section says
“For adults with overw*ight* or ob*sity, referral to this open-group behavioural weight-loss programme for at least 12 weeks is more effective than brief advice and self-help materials. A 52-week programme produces greater weight loss and other clinical benefits than a 12-week programme and, although it costs more, modelling suggests that the 52-week programme is cost-effective in the longer term.”
I scarcely know where to begin. They should probably specify that they were “more effective” by just a few pounds. And what do they mean by cost-effective in the longer term? By year two these people were already regaining their weight, with about a hundred years of data to suggest that by year five they will have gained all of it back.
To understand this interpretation, I think it’s helpful to look at the background section which explains that in the UK, where this study is conducted, the standard referral to Weight Watcher is for 12 weeks. This study is trying to make a case that the standard referral should be for 52 weeks. For 40 weeks more program fees, the average participant could lose an extra 4.4 pounds, and whether people did 12 weeks, 52 weeks, or no weeks, they are all well on their way back to their starting weight at year two.
So it seems that the only real benefit of a longer intervention would be to Weight Watchers’ bottom line, certainly not to those being referred to the program, since they are highly unlikely to actually lose weight and highly likely to end up weight cycling, which is independently linked to harm.
It may not surprise you to find that this study received funding from Weight Watchers.
So that’s the first study they cite, the second is:
2013 AHA/ACC/TOS Guideline for the Management of Overw*ight and Ob*sity in Adults
This isn’t actually a study, it’s guidelines put together based on studies (and “interpretations” of those studies) much like the one we just talked about, which means that it continues to recommend the same things that have been failing people (but generating massive profit for the weight loss industry) for the last century.
The first thing I did after skimming the guidelines was search the document for “weight watchers.”
It occurred the most (four times) in Appendix 1 - “Author Relationships With Industry and Other Entities,” which is to say that several of the guideline authors have financial ties to Weight Watchers. In fact, the majority of authors (12 of 19) have ties to the weight loss industry, with many having ties to multiple weight loss interests.
It appeared in two studies in the table of studies that were rated as “poor” (Table A–15).
One occurrence was a two-year study that found that subjects had lost weight in year one and had gained back about half in year two. (Sound familiar?)
The final appearance was a study that intended to track several different interventions, with follow-up at 6 months and 1 year. People showed weight loss at 6 months (not a surprise, short-term weight loss is very common,) but the12-month follow-up was abandoned because of “treatment crossover and only 54% participation.”
At any rate, there’s absolutely nothing in these guidelines to suggest that Weight Watchers can actually create significant, long-term weight loss.
Bottom line – Based on the research that they cite on their own website, there is no reason to believe that Weight Watchers can produce significant, long-term weight loss for more than a tiny fraction of its customers.
As a reminder, I created a quick guide to evaluate weight science studies, you can find that here. If you want more support understanding the research around weight and health, I have a video workshop (there’s a pay-what-you-can option to make sure that money isn’t a barrier,) you can check it out here.
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For a full bank of research, check out https://haeshealthsheets.com/resources/
*Note on language: I use “fat” as a neutral descriptor as used by the fat activist community, I use “ob*se” and “overw*ight” to acknowledge that these are terms that were created to medicalize and pathologize fat bodies, with roots in racism and specifically anti-Blackness. Please read Sabrina Strings: Fearing the Black Body – the Racial Origins of Fat Phobia and Da’Shaun Harrison: Belly of the Beast: The Politics of Anti-Fatness as Anti-Blackness for more on this.