Do behavioural weight programs raise eating disorder risk in adults?

Why this study matters

Behavioural weight management means structured programs that help people change eating, activity and habits, usually with support from a health professional. A common worry is that focusing on food and weight could trigger or worsen disordered eating. This review gathered the trial evidence on that question in adults. Canadian readers who are offered a behavioural program, on its own or alongside a medicine, may want to know what the research shows about this risk.

Who was in the study

The review searched four databases and clinical trial registries in March and May 2022. Of 12,023 records screened, 49 trials were eligible, with 6337 participants. Mean ages across trials ranged from 22.1 to 59.9 years, and on average 81% of participants were women (standard deviation 20.4). Everyone had overweight or obesity. Programs ran from 4 weeks to 18 months, with follow-up from 10 weeks to 36 months after the program ended. The extracted data note that Canadian participants were included in some of the studies, though the review does not give Canada-only results.

What the researchers did

This is a systematic review with meta-analysis. A systematic review finds every relevant study using set rules; a meta-analysis combines their results into one estimate. Trials were included if they tested a behavioural weight-management program in adults and measured eating disorder symptoms before and after the program or at follow-up.

The main analysis looked at within-group change, meaning how symptoms changed in people who took part in a program, rather than comparing them with a control group. The researchers used random-effects meta-analysis, a method that allows for the studies being different from one another. Results are given as Hedges' g, a standardized effect size that lets different questionnaires be pooled; a negative number here means symptoms decreased, and a number further from zero means a bigger change.

What they found

Across 20 intervention arms, global eating disorder scores fell after the programs, with a Hedges' g of -0.27 (95% CI -0.36 to -0.17). The 95% confidence interval (CI) is the range in which the true value is likely to fall. Across 49 intervention arms, binge eating fell, with a g of -0.66 (95% CI -0.76 to -0.56). Both reductions were maintained at follow-up (R32-C137).

I squared measures how much the studies disagree with each other; a higher percentage means more disagreement, and the extracted data describe both values here as substantial.

Of 14 studies that reported how many people had binge eating or binge episodes, all 14 reported a reduction. However, four studies reported eating disorder symptoms that were not present at the start in a subset of participants, ranging from 0% to 6.5%. The authors concluded that behavioural weight management does not increase eating disorder symptoms for most adults, and that a modest reduction is seen on average, but that a small subset may experience disordered eating, so monitoring for new symptoms is important.

Side effects and people who stopped

The published summary we reviewed does not report adverse events other than eating disorder symptoms, and it does not report how many people dropped out of the programs. The new-symptom finding (0% to 6.5% in four studies) is the closest thing to a harm signal in this review.

What this study does not tell you

• The main results are before-and-after changes within program groups, not comparisons against people who did not take part. That design cannot prove the programs caused the improvement.
• The studies disagreed with each other substantially (I squared 67.1% and 82.7%), so a single pooled number hides real differences between programs and populations.
• An average improvement can hide individual harm. The 0% to 6.5% of people with new symptoms in four studies is a reminder of that.
• The review covers behavioural programs only. It does not cover weight-management medicines or surgery, and it does not tell you whether combining a program with a medicine changes eating disorder risk.
• The summary we reviewed does not state the funding source. The authors reported relationships with WW, Slimming World and Novo Nordisk outside this analysis.

What it means in Canada

Behavioural support is part of Canadian obesity guidance, and it is often offered alongside medicines. This review suggests that, for most adults in trials, such programs did not worsen eating disorder symptoms, while a small number of people did develop new symptoms. It does not tell you what is right for you. For information on medicines that are often paired with behavioural programs, see semaglutide in Canada and tirzepatide in Canada. For questions about what provincial plans pay for, see public drug coverage by province.

Related reading

Other studies in this library that bear on the same question.

Source