Looking Back at Look AHEAD Part 2 - The 10% Group

This is the Weight and Healthcare newsletter! If you like what you are reading, please consider subscribing and/or sharing!In part 1 we looked at the basics of the Look AHEAD Trial of weight loss to improve cardiovascular outcomes. The trial was cancelled 9.6 years into its intended 13.5 year follow up for “futility” when analysis found no statistically significant difference in cardiovascular outcomes between a group that engaged in “intensive” caloric restriction, exercise, and, in some cases, diet drugs, and a group that got three counseling sessions a year about diabetes management.One of the claims that I often see people make is that the group that maintained at least a 10% loss had better outcomes. We saw this recently in the write-up of the Foundayo trial, in which they claimed, without context that “patients who had a weight loss of 10% or more through a lifestyle intervention had a 21% reduction in cardiovascular events.” I mentioned in that piece that this was an analysis of a small subgroup. There are some real caveats around this and other claims about the 10% weight loss group so let’s dig into it.For this we’ll look at “Four-year weight losses in the Look AHEAD study: factors associated with long-term success” by Wadden et al.As always I’ll indent the quotes so you can skip the weight stigma. In their writing ILI is the abbreviation for the weight loss group and DSE is the abbreviation for the control group.In general they discuss the weight loss:“At year 4, 35% of ILI and 18% of DSE participants achieved the study-wide goal of losing ≥7% of initial weight (P Said another way, the study goal was to produce weight loss of just 7% or more of body weight and 65% of the people who were subjected to these “intensive” interventions including diet drugs didn’t hit even that modest goal. Also, 23% of the ILI group lost 10% or more of body weight, but 10% of people in the control group that didn’t do any of these interventions did so as well. This again raises questions about the necessity of such extreme restriction even for people who believe that weight loss creates health benefits (which, again, this study does not show, since there is no way to determine if any health differences are from weight loss or behaviors, and research that actually sought to answer that question found no relationship between small amounts of weight loss and health changes in correlational analysis, and posited that it was more likely that behaviors, social support, and engagement in the healthcare system were likely to be driving the health outcomes.)The authors of the Look AHEAD paper also point out that:“significantly more DSE than ILI participants (45% vs. 26%) had gained above their baseline weight at year 4 (all P values What they aren’t being clear about is that the DSE (control) group had modest weight gain from baseline while not participating in a weight loss intervention. Meanwhile, just four years in, more than a quarter the ILI (intervention) group weighed more than when they started. Now, there is nothing wrong with being higher-weight or gaining weight, but I would say that there is something seriously wrong with a so-called healthcare intervention that subjects people to “intensive” food restriction, physical activity, and diet drugs and then has the opposite of the intended effect for at least 26% of the participants. This particularly does not age well given that we now know that the intervention would be cancelled for futility for failing to impact the intended health outcomes.When it comes to the group who lost 10% the Look AHEAD authors write that:“[Figure] 3 shows 887 ILI participants who lost ≥10% of initial weight in the first year and shows the number of these participants who achieved a loss of this size at year 4 (N = 374) or, alternatively, maintained losses of 5.0–9.9% (N = 251), 0–4.9% (N = 174), or gained above their baseline weight (N = 88). As shown, fully 42% of this subsample achieved a loss ≥10% at year 4, and a total of 70.5% maintained a loss ≥5%. It should be made clear that “fully 42% of this subsample” refers to 42% of 35% of the original sample. So out of the 2570 original people in the intervention arm, 887 participants (about 35%) lost ≥ 10% at year 1. But at year four, only 374 (about 14.5% of the original group) were still at 10%.Percentage wise, that means fewer than half of the people who had lost 10% or more of their body weight in the first year were still at or over 10% by year four and that, overall, only about 15% of the total group managed 10% weight loss for even 4 years. But there is more to this story, let’s look at their Figure 3A that shows the weight trajectory of this group:Image text: Figure 3 A. Weight loss trajectories over 4 years in the 887 participants in the Intensive Lifestyle Intervention (ILI) who, at year 1, lost ≥ 10% of initial weight. The figure shows the number of participants who, at year 4, maintained a loss of 10% or more of initial weight (N = 374), of 5.0–9.9% (N = 251), or of 0–4.9% (N = 174) or who gained above their baseline weight (N = 88).You’ll note that everyone has regained from their low point, 9.9% (88 people) had already regained more weight than they lost and the majority are still on a trajectory to continue to gain weight after this follow up.If we go back to their quote, they claim that this figure shows percentages of people who “maintained losses of 5.0–9.9% (N = 251), 0–4.9% (N = 174).” I do not think that the word “maintained” reflects the reality that these people’s weight trajectory is going straight up. Catching a group of people at 5% weight loss on their way up is not the same thing as “maintaining” a 5% weight loss.Content note: This next section talks about calories, exercise, disordered eating/eating disorders, if that may be harmful to you you can scroll down to “Discussion.”The researchers note that “Participants who maintained the [10%] loss, compared with those who did not, attended more treatment sessions and reported more favorable physical activity and food intake at year 4.”Again, this begs the question as to whether behavior or weight loss actually created any health difference. It also begs another, much more troubling question. Below is their Figure 4 which shows the characteristics of the subset of subjects who took self-reported surveys about their food and exercise behaviors. Note that those who maintained a 10% loss in general were consuming about 1565.5 calories a day (fewer than the 1,570 calories subjects in the Minnesota STARVATION study were given during the starvation stage) and burning about 2,000 calories weekly through exercise. Applying the Paffenburger Activity Questionnaire that these authors are using to the Minnesota STARVATION study participants, those participants were expending about 2200 calories per week. One thing the authors don’t mention in this sub analysis, or the original analysis, is the possibility that they created disordered eating/eating disorders in part of their population and then celebrated it as “long-term success.”DiscussionThe first sentence of their discussion section states:“Participants in the Intensive Lifestyle Intervention achieved a 4.7% reduction in initial weight at year 4. This loss is among the largest reported at this length of follow-up for individuals in a randomized controlled trial who were treated by a lifestyle intervention”I do not think that this is the flex they think it is. Giving people less food and similar activity to a study on starvation over four years produces 4.7% weight loss - an amount of weight that some people fluctuate monthly through their menstrual cycle? The phrase “who cares?” comes to mind.To further demonstrate the issues with this study, in the discussion section these authors compare their “maintainers” to the National Weight Control Registry which I have discussed before as perhaps the worst example of the truly ridiculous methodology that passes for “science” when it comes to weight loss and health.In general, when people cite the Look AHEAD study as proof of efficacy of weight loss interventions, you can suggest that they look back at the actual findings of the study. Even these authors are honest that “Look AHEAD’s study design prevents us from definitively determining the contribution to long-term weight loss of the lifestyle intervention’s different treatment components.” What they aren’t so clear about is that Look AHEAD’s study design prevents them from knowing if weight loss had anything to do with any of the health benefits.Especially since, as we talked about in part 1, research finds that weight-neutral interventions can produce similar or greater benefits with less risk. In general, whenever someone claims that a study shows that weight loss creates health benefits, the first question you can ask is “what mechanism was used to determine whether weight loss or behavior change created the differences in outcomes?” If there isn’t one, then they can’t conclude that weight loss did anything at all.If you want to learn how to read between the lines of weight and health research, this month’s online workshop is about exactly that. I’ll teach you the basics of breaking down research and analyzing media article and social media to break through the BS and get to the truth of what the research finds (and what it doesn’t). There is a pay-what-you-can option so money isn’t a barrier and all registrants get a video. Details and Registration here!If you appreciate the work I do here, you can support my ability to do it by becoming a free or paid subscriber!Liked the piece? Share the piece!More researchThe Research PostMore resourcesThe Resource Post*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’s Belly of the Beast: The Politics of Anti-Fatness as Anti-Blackness for more on this. 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