CNR1 and obesity due to melanocortin 4 receptor deficiency: Endocannabinoids, via CB1, have a recognized role as orexigenic factors, in that they stimulate food intake and body fat deposition [26,43]; at the periphery ECS activity is largely reported in the gastrointestinal tract, and liver and adipose tissue, along with possible involvement in the microbiota–gut–brain axis and obesity onset, as excellently reviewed in [23].