TCF7L2 and metabolic syndrome: Indeed, high dietary SFA intake (≥15.5% energy) impairs insulin sensitivity and increases the risk for metabolic syndrome in carriers of the T risk allele of TCF7L2 rs7903146 polymorphism relative to CC homozygotes [36] Likewise, high dietary SFA intake (≥11.8% energy) leads to increased waist circumference and consequently increases the risk for metabolic syndrome in carriers of the C risk allele of CLOCK rs1801260 [31].