Diet therapy is an effective method for treating obesity. However, its effectiveness varies from person to person. With that in mind and working towards the implementation of personalized nutrition education, we investigated the relationship between aspects of oriental medicine and genes related to obesity. We analyzed three genes associated with obesity (ADRB 3, UCP 1, and ADRB 2) and classified them as either wild type or mutant. The presence or absence of gene polymorphisms in the obesity-related genes was analyzed by using PCR-CTPP. We conducted a survey using questions that would be comprehensible to people unfamiliar with oriental medicine in order to assess their body constitution, by diagnosing two elements of body constitution according to oriental medical theory (stomach heat [wei re] and spleen vacuity [pi xu]). The study was conducted in 81 women and 28 men (mean age, 42.6 years ; mean BMI, 22.3 kg/m²). Among them, 7 participants were underweight, 83 were of normal weight, and 19 were overweight. The results of the analysis revealed that BMI was highest in those with stomach heat and lowest in subjects with spleen vacuity. Wild type ADRB 3 increased susceptibility to stomach heat, which led to higher body weight ; whereas, the presence of mutated ADRB 3 increased the likelihood of spleen vacuity, which led to lower body weight. These results suggest that by making comprehensive assessments of body characteristics, it is possible to identify individuals with a predisposition to obesity or low body weight.