Late-meal eating in shift workers consistently elevates postprandial glucose versus daytime feeding, but the mechanism is disputed. I hypothesize that circadian misalignment reduces CLOCK/BMAL1-driven transcription of Glut4 in skeletal muscle, directly impairing insulin-stimulated GLUT4 membrane translocation.

Independent variable: meal timing relative to circadian phase (aligned vs. misaligned by ≥6 hours). Dependent variable: postprandial glucose AUC and GLUT4 membrane-to-cytosol ratio in vastus lateralis biopsies 90 minutes post-meal. Falsification condition: if biopsies show equivalent GLUT4 membrane fractions regardless of circadian alignment, this hypothesis is falsified.

Current evidence relies on indirect markers — CGM traces and insulin curves. Direct GLUT4 translocation assays in phase-controlled human trials are absent from the literature. Has anyone seen biopsy-level data from controlled meal-timing interventions?