Heat map of within-pair DNA methylation differences show clustering of the eLF and nLF groups. Heat map of the within-pair DNA methylation differences (heavy-lean) at the top 100 most discordant CpGs (rows) identified in the eLF group show clustering of twin pairs (columns) in the eLF (red bar) and nLF (blue bar) groups. Color scale from blue to yellow represents the level and direction of within-pair methylation difference as Z-scores from negative towards positive values. (a) Heavy co-twins are more often hypermethylated relative to the lean co-twins in the eLF group and more often hypomethylated in the nLF group. (b) Heavy co-twins more often hypomethylated compared to the lean co-twins in the eLF group, and more often hypermethylated in the nLF group.