The aim of the current study is to evaluate whether L-Methionine supplementation (L-Met-S) improves type 2 diabetes-induced alterations in glucose and lipid metabolism by modulating one carbon metabolism and methylation status.Diabetes was induced in male Sprague Dawley rats using high fat diet and low dose streptozotocin. At the end of study, various biochemical parameters, immunoblotting, qRT-PCR and ChIP-qPCR were performed. We provide first evidence that L-Met-S activates p-AMPK and SIRT1, very similar to 'metformin'. L-Met-S improves the altered key one-carbon metabolites in diabetic rats by modulating methionine adenosyl transferase 1A and cystathione β synthase expression. qRT-PCR shows that L-Met-S alleviates diabetes-induced increase in Forkhead transcription factor 1 expression and thereby regulating genes involved in glucose (G6pc, Pdk4, Pklr) and lipid metabolism (Fasn). Interestingly, L-Met-S inhibits the increased expression of DNMT1 and also prevents methylation of histone H3K36me2 under diabetic condition. ChIP assay shows that persistent increase in abundance of histone H3K36me2 on the promoter region of FOXO1 in diabetic rats and it is recovered by L-Met-S.We provide the first evidence that dietary supplementation of L-Met prevents diabetes-induced epigenetic alterations and regulating methionine levels can be therapeutically exploited for the treatment of metabolic diseases. This article is protected by copyright. All rights reserved.