Are Overly Enthusiastic Interpretations of Lifestyle Studies Harming People Living With Obesity?Thursday, August 12, 2021
As for many chronic diseases, there is certainly a role for dietary and other behavioural measures in the management of obesity.
But let us not kid ourselves. According to all of the available evidence, diet and exercise (often described as “lifestyle” interventions) simply do not come close to measuring up with medication or surgical treatments for obesity.
Nevertheless, we continue to see overly enthusiastic reports on the efficacy (not effectiveness!) of lifestyle interventions, which not only tend to oversell the benefits but also ignore the reality that most of these interventions that may work more or less in clinical trials, would be almost impossible to implement with any degree of fidelity in routine clinical practice.
Case in point, the Look AHEAD study. This was certainly one of the most ambitious and best-resourced randomized controlled trials of intensive lifestyle intervention, designed and run by the leading experts in the field with the aim of once and for all demonstrating the benefit of weight loss on cardiovascular morbidity and mortality (albeit in elderly patients with type 2 diabetes).
Indeed, not only was running the trial (till its abandonment for futility) a major logistical feat, but there were certainly several indicators of benefit, even if not in the primary endpoint of the study.
These benefits are now nicely summarized and highlighted in a paper by Rena Wing on behalf of the Look AHEAD Research Group in a recent issue of OBESITY.
While the paper highlights a number of secondary outcomes that were apparently improved in the intensive lifestyle intervention (ILI) group, the article also notes that,
“…several important outcomes (cardiovascular morbidity and mortality, cancer, and cognition) did not show significant differences between ILI and control, and frailty fractures occurred more often in ILI than in control.”
As much as the many post-hoc analyses discussed in this paper suggest health improvements in various aspects in the ILI group, the authors also state that,
“There were also some subgroups that appeared to have poorer outcomes in ILI relative to DSE, most notably those who had the highest BMI at the start of the trial and those with poorer initial health, including a history of CVD and more health deficits at baseline.”
Based on these findings, the authors conclude that,
“it would seem best to recommend ILI early in the course of diabetes, when individuals are younger, hopefully have less obesity, and before they have developed other comorbidities.”
While no one can argue with this last statement, this is not how the Look AHEAD is often portrayed or interpreted.
Thus, for e.g. in a guiding document that German payers use for deciding which patients get reimbursed for bariatric surgery, the Look AHEAD study is considered proof that lifestyle interventions work and therefore held up as justification to deny bariatric surgery, when in fact this study shows nothing of the sort.
This overly enthusiastic interpretation of the rather modest, and in many ways disappointing, results of the Look AHEAD study, is not uncommon, and is potentially harming patients living with obesity, when used to argue against the need for surgery or medication.
It is perhaps time that we start focussing on the now well-documented limitations of “lifestyle” interventions for obesity and stop pretending (or hoping) that these interventions will be enough for managing obesity in the majority of people living with this chronic disease.