GDF15 and obesity due to melanocortin 4 receptor deficiency: In this context, two different pathways are envisaged: 1) taking advantage of its proprieties as an appetite suppressor, a weight loss promoter, and an agent against insulin resistance to build a pharmacologically administered GDF15 analogue acting as a GFRAL agonist to treat obesity, diabetes and prediabetes, or 2) to block GFRAL receptor signalling through GDF15 analogues acting as GFRAL antagonists, for the treatment of diseases in which GDF15 is highly expressed, such as cancer‐induced anorexia or cachexia.