GCG and diabetes mellitus: He et al. (2015) reported that in a study of rats with obesity and diabetes, RYGB led to significant induction of autophagy in the liver, restored autophagy levels in the liver and was associated with reducing the level of hepatic lipids. Increased autophagy in the liver after RYGB was well correlated with plasma GLP-1 levels (He et al., 2015). Therefore, induction of GLP-1 after bariatric surgery would also lead to significant stimulation of autophagy (Figure 4).