Drugs that bind to and activate the receptors for the hormones GLP-1 and GIP are effective in the treatment of obesity and diabetes. Surprisingly, active substances are currently being developed that not only activate the GIP receptor (agonists) but also block it (antagonists). They also have a positive effect on body weight. A team from Helmholtz Munich, the German Center for Diabetes Research (DZD) and Ludwig-Maximilians-Universität München (LMU) has now discovered that GIPR agonism and antagonism engage different mechanisms to decrease body weight and food intake. These new findings could pave the way for more targeted medication against obesity.