BackgroundThe A allele of rs9939609 polymorphism at the FTO gene has been consistently associated with higher body mass index in different populations, but conflicting results have been found regarding its contribution to food intake variability. ObjectiveThis study aimed to investigate the association between this genetic variant and nutrient and food intake in an urban Argentinian population. DesignA cross-sectional, analytic investigation was performed between October 2018 and February 2020. Participants/settingsAdults of both sexes residing in La Plata, Argentina, were recruited through social networks (Instagram and Facebook). Of 179 eligible adults, a total of 173 adults were included in the final analyses. Outcome measuresNutrient and food group intake data were obtained by an interview-administered food frequency questionnaire. Height and weight were measured, and genotypes were obtained by real-time polymerase chain reaction. Statistical analysesThe per-allele effect on nutrient and food group intake was assessed by general linear models, adjusting for age, sex, educational level, total energy intake, and body mass index. Dietary patterns were derived by principal component analysis. The association of the A allele with adherence to each dietary pattern was also evaluated by the general linear model. ResultsThe frequency of the risk allele was 27%. A-carriers showed a higher total fat (1.88 [0.55, 3.21] % of total energy intake), saturated fatty acids (0.82 [0.25–1.39] % of total energy intake), and monounsaturated fatty acids (0.66 [0.08, 1.24] % of total energy intake), and a lower carbohydrate (−1.99 [−3.48, −0.50] % of total energy intake) intake than TT homozygous. A-carriers also reported a higher “milk and yogurt” (1.08 [0.24, 1.91] % of total energy intake), “animal fats” (1.09 [0.14–2.03] % of total energy intake), and fat-rich ultraprocessed foods (2.10 [0.52, 3.67] % of total energy intake) intake in comparison with TT homozygous. Furthermore, A-carriers showed higher adherence to the Western dietary pattern. ConclusionThe A allele contributed to nutrient and food intake variability in the studied population and was associated with the consumption of saturated fatty acids–enriched foods.