Anatomically modern humans (AMHs) exhibit a significant increase in basal metabolic rate (BMR) and height compared to non-human apes. This study investigates the genetic basis underlying these traits. Our analyses reveal a strong genetic correlation between height and BMR. A regulatory mutation, rs34590044-A, was found to be associated with the increased height and BMR in AMHs. rs34590044-A upregulates the expression of ACSF3 by increasing its enhancer activity, leading to increased body length and BMR in mice fed essential amino acids which are characteristic of meat-based diets. In the British population, rs34590044-A has been under positive selection over the past 20,000 years, with a particularly strong signal in the last 5,000 years, as also evidenced by ancient DNA analysis. These results suggest that the emergence of rs34590044-A may have facilitated the adaptation to a meat-enriched diet in AMHs, with increased height and BMR as consequences of this dietary shift.