To determine the effects of the estrogen-related receptor γ (ESRRG) rs1890552 A > G polymorphism on dietary advice-mediated changes in fasting glucose and arterial stiffness, 374 subjects with normal fasting glucose (NFG; control group, no treatment) and 142 subjects with impaired fasting glucose (IFG group, dietary advice) were followed for 3.5 years. At follow-up, the GG subjects in the IFG group showed a significant reduction in fasting glucose, which was greater than in the AA subjects. A significant association was observed between ESRRG rs1890552 A > G polymorphism and changes in fasting glucose, brachial-ankle pulse wave velocity (ba-PWV), and 8-epi-prostaglandin F2α in the IFG subjects. At baseline, the GG subjects showed a higher ba-PWV than the AA subjects in the IFG group. At the 3.5-year follow-up, subjects with AA or AG showed significant increases in ba-PWV, whereas subjects with GG showed a decrease from baseline. This study suggests that the ESRRG rs1890552 A > G polymorphism may modulate interindividual differences in atrial stiffness, with a reduction in fasting glucose in response to dietary advice in subjects with IFG after a 3.5-year follow-up.