GCG and obesity due to melanocortin 4 receptor deficiency: It will be important to assess the longer term impact of the introduction of health policies that have come into force since 2018, such as the soft drinks industry levy or “sugar tax,”21 and the calorie labelling regulations,22 plus what therapeutic advances such as GLP-1 (glucagon-like peptide 1) agonists will have on obesity prevalence going forward.