Effects of Personalized Nutrition Education Tailored to Individual Genetic Risk Profiles on Weight Loss in Adults with Obesity: A Randomized Controlled Trial

Background/Objectives: Responses to lifestyle interventions vary widely in obesity, and genetic factors may enhance outcomes. This study evaluated whether a 12-week genotype-informed personalized nutrition education (GEN) program improved weight and overall body composition among adults with obesity. Methods: Adults with a body mass index ≥ 25 kg/m2 were randomized to a genotype-informed personalized nutrition education (GEN) group or a control group receiving standard nutrition education. The GEN group received weekly counseling tailored to nine obesity-related genetic traits. Changes were evaluated using paired t-tests and repeated-measures analysis of variance, with significance defined as p < 0.05. Results: Forty-three participants (GEN: n = 19; CON: n = 24) were analyzed. After 12 weeks, the GEN group showed significantly greater reductions than the CON group in body weight (−3.35 ± 0.7 vs. –0.91 ± 0.4 kg, p = 0.004), BMI (–1.17 ± 0.3 vs. –0.32 ± 0.1 kg/m2, p = 0.005), and waist circumference (–5.56 ± 0.8 vs. –2.53 ± 0.7 cm, p < 0.001). Energy (–415 kcal, p = 0.003) and carbohydrate intake (–65 g, p = 0.003) also decreased significantly in the GEN group. Exploratory subgroup analyses suggested that participants classified as high genetic risk showed more pronounced improvements when receiving genotype-informed counseling. No serious adverse events were reported. Conclusions: The genotype-informed personalized nutrition program was associated with greater improvements in body composition than general nutrition education. Integrating genetic risk information into structured nutrition education may enhance perceived personal relevance and support effective weight management.