A clinical trial with 48 NAFLD patients demonstrated that a daily dose consumption of 400 mg green coffee extract for 8 weeks could improve fasting blood glucose (mean difference (MD): −11.50; 95%CI: −19.59, −3.42), insulin resistance status (MD: −0.97; 95%CI: −1.84, −0.11), body weight (MD: −1.73; 95 % CI: −2.44, −1.01), body mass index (BMI) (MD: −0.57; 95%CI: −0.84, −0.29), and waist circumference (MD: −3.69; 95%CI: −5.85, −1.54), as well as increasing the serum level of leptin [166]. The gene discussed is LEP; the disease is Insulin resistance.