Abstract
BACKGROUND/OBJECTIVES: The consumption of highly palatable ultra-processed foods (UPFs), enriched in sugar, saturated fat, and salt, increases the risk of morbidity and mortality by inducing obesity, type 2 diabetes (T2DM), cardiovascular disease, and cancer. The present study aimed to investigate the impact of a UPF-rich diet on adiposity, feeding behavior, glucose homeostasis, intestinal barrier markers, expression of inflammatory cytokines, and microbiota in male and female C57BL/6J mice. METHODS: Animals received a chow diet or a UPF diet for 10 (UPF10) or 30 days (UPF30). UPF10 induced greater calorie intake as early as 10 days on a UPF diet. Fat accumulation occurs in both sexes, specifically after 30 days of exposure. RESULTS: The duration of UPF exposure significantly influenced glucose metabolism and insulin sensitivity. A 10-day UPF diet was associated with lower fasting blood glucose levels, without higher insulin levels, in both sexes. Females showed early impairment in glucose tolerance. Male mice on UPF30 exhibited elevated systemic IL-6 levels, as well as reduced intestinal expression of Occludin and E-cadherin genes. In females, UPF30 increased TNF-α expression in the gut and increased microbial diversity. Both sexes displayed dysbiosis, with females showing pronounced changes in the proportion between predominant phyla, and males showing more specific changes in bacterial genera. CONCLUSIONS: A diet high in UPFs promoted metabolic, inflammatory, and gut microbiota alterations, with effects varying according to exposure duration and biological context, and becoming more pronounced after 30 days.