The triad association between Type 2 Diabetes Mellitus (T2DM), Metabolic Associated Fatty Liver Disease (MAFLD) and incretin secretion dysfunction, including GLP-1 (Glucagon-Like Peptide-1) maintains a critical cardiovascular risk and liver-related mortality. The aim of this study is to establish interactions between the GLP-1 plasma levels and metabolic syndrome clusters and adipokines profile (leptin, adiponectin, resistin) and proinflammatory cytokines (TNFα, IL-6, IL1β, IL-17) in diabetic subjects with or without MAFLD. The data revealed that insulin resistance (Homa-IR) is present in all groups. Homa-IR is negatively associated with plasma GLP-1 depletion in the MAFLD, T2DM and MAFLD + T2DM groups. Adiponectin levels are decreased in all groups as for GLP-1. At the opposite, leptin, resistin, TNFα, IL-6, IL1β and IL-17 levels show an inverse correlation with GLP-1. It appears that plasma GLP-1 can be considered as a transition and evolution biomarker in MAFLD and T2DM. GLP-1 accurately reflects metabolic and inflammatory status, both in subjects with MAFLD only or with T2DM only, before the Diabetes - Steatosis stage.