High-Frequency Feeding With Late-Night Snacking Accelerates Type 2 Diabetes and Alters Diurnal Metabolic Gene Expression in Male KKAy Mice

We investigated whether sustained high-frequency feeding (six meals per day) increases type 2 diabetes mellitus (T2DM) incidence and alters diurnal metabolic patterns in male KKAy mice. Mice were randomly assigned to three or six isocaloric meals per day for 60 days. Metabolic phenotyping, tissue glycogen assays, multitissue circadian clock gene analysis, and exploratory correlation analyses of gene coexpression were performed. Our results demonstrated that high-frequency feeding significantly increased body weight, fasting glucose levels, and T2DM incidence (relative risk = 2.1) compared with three-meal feeding. Six-meal feeding exhibited larger diurnal glucose/insulin oscillations, earlier and higher hepatic glycogen accumulation, disrupted muscle glycogen rhythmicity, and elevated expression of hepatic metabolic genes. Exploratory correlation analyses revealed altered diurnal coexpression patterns among clock and metabolic genes, although causal or regulatory inferences are not warranted from mRNA-level data alone. These findings support meal frequency as an independent modulator of metabolic health and provide preclinical evidence relevant to chrononutrition strategies for T2DM prevention. Article Highlights Meal frequency as an independent determinant of type 2 diabetes mellitus (T2DM) risk under strictly isocaloric conditions remains undefined. We investigated whether increasing meal frequency from three to six isocaloric meals per day alters T2DM incidence and diurnal metabolic and gene expression patterns in male KKAy mice. High-frequency feeding with late-night snacking significantly increased T2DM incidence (relative risk = 2.1), disrupted diurnal glucose and insulin rhythms, increased hepatic glycogen accumulation, and elevated hepatic metabolic gene expression, with altered diurnal coexpression patterns. These findings establish meal frequency as an independent modifier of metabolic health and provide preclinical evidence supporting chrononutrition-based strategies for T2DM prevention.