Here, we measured cannabinoid 1 receptor (CB1R) availability using positron emission tomography (PET) with [18F]MK-9470 in 54 patients with food intake disorders (FID) covering a wide body mass index (BMI) range (anorexia nervosa, bulimia nervosa, functional dyspepsia with weight loss and obesity; BMI range=12.5–40.6 kg/m2) and 26 age-, gender- and average BMI-matched healthy subjects (BMI range=18.5–26.6 kg/m2). The gene discussed is CNR1; the disease is obesity due to melanocortin 4 receptor deficiency.