Impact of ultra-processed foods on hedonic and homeostatic appetite regulation: A systematic review

The rapid rise in ultra-processed foods (UPF) consumption correlates with the growing global obesity prevalence. Investigating the hedonic and homeostatic mechanisms affected by UPF may provide insights for obesity prevention and appetite regulation. This systematic review aimed to examine the current understanding of the potential effects of UPF on appetite regulation and food intake, examining both hedonic and homeostatic pathways. A search was performed in PubMed, Scopus, Web of Science, and EMBASE databases, and studies published in English language were selected. Study selection and inclusion/exclusion criteria were determined based on PECOS framework. The quality of the studies was evaluated using appropriate Cochrane Risk of Bias tools and all articles were found to have low risk of bias. Of the 11 studies included, three were randomized controlled trials, one was cross-over study, one was non-randomized controlled study, and six were observational studies. Results indicated that UPF consumption may influence to hedonic appetite by promoting faster eating rates, enhancing palatability, activating brain reward circuits, and potentially increasing food addiction behaviors. Additionally, UPF intake may disrupt homeostatic appetite regulation by altering gut-brain axis signaling and modulating peripheral peptides such as ghrelin, GLP-1, GIP, and PYY. However, findings on both hedonic and homeostatic mechanisms remain inconclusive due to heterogeneous study designs, general characteristics of participants, and varying baseline UPF intake. These findings suggest that reducing UPF consumption could be a relevant target for appetite and weight management strategies, highlighting the need for more mechanistic and longitudinal research.