Weight Regain after Lifestyle Interventions is Associated with Higher Risk of Liver Inflammation: A Retrospective...

Lifestyle-induced weight loss improves metabolic health, but weight regain is common. Its hepatic consequences, particularly in relation to metabolic dysfunction-associated steatotic liver disease (MASLD), remain insufficiently characterized.

This retrospective observational study included 213 patients categorized as weight regain (≥5% lifestyle-induced weight loss followed by return to or exceeding baseline weight) or weight sustain (weight change within ±5% of baseline) over 3 years. Propensity score matching (PSM) balanced age, sex, weight, and body mass index. Clinical, biochemical, and noninvasive liver indices were compared. In a bariatric surgery subset, liver histology, transcriptomics, quantitative PCR, and immunohistochemistry were performed.

No significant differences were found in metabolic parameters between groups. After PSM, the weight regain group showed higher alanine aminotransferase (ALT) (median 59.00 vs 41.00 IU/L, P=0.007) and aspartate aminotransferase (AST) (33.50 vs 26.00 IU/L, P=0.041). In males, ALT (88.00 vs 47.00 IU/L, P<0.001) and AST (46.00 vs 30.00 IU/L, P=0.004) remained higher. Noninvasive indices of hepatic steatosis (Dallas Steatosis Index, DSI) and fibrosis (NFS, FIB-4) did not differ. In male patients with liver biopsy samples available, liver histology showed comparable NAFLD Activity Scores (NAS) and fibrosis stages, whereas transcriptomic analysis revealed immune-related pathway enrichment. Increased hepatic CD11B and CD68 expression was confirmed by quantitative PCR and immunohistochemistry.

Weight regain after lifestyle-induced weight loss is associated with early liver-related biochemical abnormalities and hepatic innate immune activation in the absence of advanced fibrosis, underscoring the need for early liver risk assessment in individuals with weight cycling.