These results demonstrate that there are mutual effects of dietary fat with gender, BMI, and FAAH rs324420 on HDL‐C levels, which pave a novel way to explore the heterogeneous relationship of serum lipid profiles with diets or FAAH rs324420 and provide a new perspective of precision dietary interventions of dyslipidemia, especially in adolescents. The gene discussed is FAAH; the disease is metabolic syndrome.