However, effect sizes for the individual clocks were very small (most r < 0.1), with the exception of moderate correlations between the metabolomic clock and obesity and metabolic syndrome (r ~ 0.2), and the composite score effect sizes were only slightly stronger (most r ~ 0.1; r ~ 0.3 for obesity and metabolic syndrome). Here, CLOCK is linked to obesity due to melanocortin 4 receptor deficiency.