GHRL and obesity due to melanocortin 4 receptor deficiency: There is great variability in the results of studies correlating endogenous postprandial plasma ghrelin concentrations and measures of eating behavior, including appetite ratings and food intake, likely related to often small samples sizes; differences in study design and obesity status; specificity of ghrelin immunoassays to AG, DAG, or both; use of protease inhibitors to prevent breakdown of AG to DAG; use of absolute or changes in plasma ghrelin; and lack of correction of food intake for body size or resting energy expenditure (see Supplementary References for list of publications [25]).