Background: The aim of this review was to synthesise available evidence from published RCTs on changes in dietary intake and diet quality in studies prescribing liraglutide, semaglutide or trizepatide, in patients of all age groups undergoing weight-loss therapy and/or for glyceamic management with and without T2DM.
Methods: Peer-reviewed papers published in English were obtained through five online databases. Searches covered the period between January 2008 and March 2024. Eligible studies were phase 3/4 RCTs prescribing liraglutide, semaglutide or tirzepatide; and included a dietary intervention component.
Results: Upon completing full-text screening (n=1,584), 42 individual studies were included. Most of the included studies were phase 3 trials (76%), targeting adults (93%) and more than half (57%) were conducted at multiple sites and across multiple countries. Energy intake restriction (i.e., 2000kj/500kcal deficit) composed the dietary component in n=25 studies, although this was predominantly made up of three larger trials (i.e., STEP, SCALE and SURMOUNT). Approximately 33% of studies included no description of what constituted their dietary component. More than half (55%) reported that the dietary component was delivered by a dietitian and/or qualified health professional. Approximately half (45%) of the studies reported the use of food records (e.g., food diaries) as part of the intervention to encourage adherence. While some provided a brief explanation of using food diaries as part of the participants’ diet counselling sessions (e.g., STEP trials), all studies lacked detailed methods of how the data was used and no studies reported food intake as an outcome.
Conclusion: Overall, the inclusion of dietary intervention details has been poorly included and/or described in studies prescribing liraglutide, semaglutide or trizepatide. There is a need for studies reporting change in dietary intake overtime, particularly given medication related side effects that are potentially ameliorated by dietary change.