FGF21 and obesity due to melanocortin 4 receptor deficiency: We further showed that the effect sizes of the associations between macronutrient intake and plasma FGF21 were somewhat attenuated but still highly significant when restricting to individuals with obesity (BMI ≥30) (Supplementary table 3) and when restricting to individuals that had fasted for at least 6 h before given their blood sample (Supplementary table 4).