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Key Words That Have a Different Meaning In Weight Science Research
In the twenty-ish years that I’ve been studying weight science research, I’ve noticed that there are some common words that seem to mean different things in weight science research than, well, anywhere else. This is not to say that these things don’t happen in other research as well, thought it’s perhaps more common in weight loss research that these “alternative meanings” tend to create more support for the weight loss paradigm, by whose proponents the studies are often funded and/or conducted, and for whom the idea that people can succeed at significant, long-term, weight loss is crucial to their careers/profits.
Let’s take a look:
If you read a lot of weight science/weight loss research you might feel like the concept of “long term” has entirely lost its mooring to meaning. That’s something that seems, to me, to have been very intentional in many cases. Even if it’s not intentional, it’s still a problem.
The research that we have shows that most people lose weight in the first year and regain that weight within 2-5 years. When the FTC was questioning weight loss companies, including Weight Watchers about their deceptive trade practices, they asked them to conduct studies of at least five years. They refused, protesting that “it would be too depressing for our clients.”
What we see in practice is that weight loss research can be as short as a few weeks. So based on that, studies with durations of 6, 12, 18 months will claim to show “long-term” follow-up. Obviously, this is too short to capture the weight regain that the existing evidence suggests will occur. Based on Weight Watcher’s comments, that may well be the point.
Another issue here is studies that have two follow-up periods – maybe 1 year and 2 years. Then they label those “short-term” and “long-term” follow-ups. This may not be done with the goal of misleading (though, let’s not rule that out) but the result is the same. When we’re talking about an intervention that is supposed to impact people (or that, in fact, is supposed to be delivered to people) for the rest of their lives, people assume that long-term follow-up will approximate that kind of duration, not be two years from the start of the study. (Of note, often the so-called “follow up” time includes the intervention time. For example, subjects will be placed on a drug protocol for a year, and then they will be followed up with one year later. That will be called a “two-year follow-up” but, in fact, it’s a one-year follow-up after a one-year intervention.)
There are lots of ways that significant goes wrong. In some cases, it’s based only on the sincerely held beliefs of the researcher(s). I was once discussing the folly of a study that called a loss of 3% of the participants’ body weight “significant” with a researcher (not the author of the paper we were discussing.) He said “there are doctors who might consider that loss significant.” That is precisely the problem. We have allowed the weight loss industry to keep moving the goal post on what is considered “significant” weight loss until it can be achieved with a good loofah scrub and a beard trim. If I said that I had a quart of milk and I was going to leave you a significant amount of it for your breakfast, I imagine that you and your cereal would be pretty bummed when you opened the fridge to find less than two tablespoons of milk left (3% of that quart). I wrote about this in more depth here.
There’s also the confusion of “statistically significant” (which just means that, however small the amount of weight loss, it’s more likely that it was caused by the study intervention than by chance) with the common definition of “significant” as a reasonably large amount.
This can go wrong when people use “statistically significant” because it sounds like an important, science-y term and they hope other people will think that too. Then there’s the use of “significant” in a study conclusion (ie: participants experienced significant weight loss) but when you read the study (which is often behind a paywall,) you find that the weight loss was very small but statistically significant.
Finally, “significant” (or “statistically significant”) are often used where one might expect (and it would be very helpful to have) the actual results of a weight loss intervention. So they say “most participants experienced significant weight loss” rather than “the average participant lost five pounds in two years.” (See also – my roommate left me a significant among of milk vs my roommate left me less than 2 tablespoons of milk.)
Here’s where it all comes together. Subjects of a study lose a couple pounds for a couple months. The intervention is declared successful, the implication being that if these subjects can lose a couple of pounds in a couple of months, then anyone can lose any amount of weight over time using the same method. This is, of course, not at all scientific, but scientific is another of those words that seem to lose their meaning in weight science research. In another example, subjects of a study lose 10 pounds in year one, gain back 5 pounds in year two, they end the study and declare it a success (assuming, without any basis, that the trajectory of weight regain, which was going straight up, leveled off the moment that they stopped observing it.)
As a bonus, neither of these studies will have tracked any actual health outcomes, but because of the (unscientific) assumption that weight loss (and not the behavior changes that preceded it) creates health benefits, both of these studies will claim to have improved the health of the participants.
To use the plainest language possible - this is bad. It’s really, really bad. It props up an utterly failed (but massively profitable) weight loss paradigm and keeps fat* people from receiving ethical, evidence-based healthcare. And it’s frustrating that it’s been happening for so long. If you are in a position with privilege/power/leverage when it comes to research, please do whatever you can to push for better research (and to push for money to be made available for research of weight-neutral interventions.)
If you are someone who is reading the research, or depending on it for your healthcare practice, take the time to dig into it and see what it really says. Let these words be blinking red lights to dig deeper and ask more questions. If you want to do a deeper dive into research, I have a quick guide for evaluating weight science research here.
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*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.