Could weight-loss drugs eat the world?

Since the late 1980s scientists believed that a gut hormone called glucagon-like peptide-1 (GLP-1), which is secreted by the intestines after a meal, could help treat diabetes. GLP-1 increases the production of insulin (a hormone that lowers blood-sugar levels) and reduces the production of glucagon (which increases blood-sugar levels). But GLP-1 is broken down by enzymes in the body very quickly, so it sticks around for only a few minutes. If it were to be used as a drug, therefore, patients would have faced the unwelcome prospect of needing GLP-1 injections every hour.