A systematic review of interventions to increase physical activity and reduce sedentary behaviour following bariatric surgery.

None of the twelve studies was powered to detect a change in physical activity or sedentary behaviour after surgery, so no single study was set up to answer the question the review asks. Every study was judged to have at least some concerns for risk of bias, and several were rated high, largely because participants cannot be blinded to an exercise or counselling programme and physical activity was often self-reported. No study reported whether the intervention was delivered as intended, so a lack of effect could reflect poor delivery rather than an ineffective intervention. Control conditions were poorly described, making it hard to tell what the intervention was actually being compared with. Only six of the twelve studies set out with physical activity as an aim or hypothesis, and only one aimed to reduce sedentary behaviour, so most studies measured these behaviours incidentally. The studies were too different in their outcomes and measurement tools to be combined in a meta-analysis. Most participants were women and most studies mixed several types of weight-loss operation, so the findings may not apply to men or to a single procedure. Grey literature was not searched and papers not published in English were excluded.

The review was funded by a National Institute for Health Research Clinical Doctoral Research Fellowship held by the first author; the authors state the views are their own and not those of the NHS, NIHR or the Department of Health and Social Care. Six authors declared nothing to declare. One author reported grants from the NIHR during the study and grants, personal fees and other payments from a list of pharmaceutical companies, including Novo Nordisk, AstraZeneca, Boehringer Ingelheim, Takeda, Lilly and Sanofi, all outside the submitted work.

Do not treat the behaviour change techniques listed in this review as a tested recipe for getting patients moving. The authors describe the support for them as preliminary, none of the studies was powered to detect a change in physical activity or sedentary time after surgery, and seven of the twelve found no difference on those outcomes.