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

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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%