<p>Gender differences in carbohydrate metabolism may influence obesity risk, but evidence from Asian populations remains limited.This study aimed to examine the associations of high-carbohydrate and high-fat dietary patterns with obesity, with gender comparisons, among Thai adults in Bangkok. This cross-sectional study used convenience sampling and included 380 adults (83 men, 297 women) aged 18–59 years from Laksi district, Bangkok, Thailand. Overweight and obesity were defined according to Asian WHO classifications. Dietary intake was assessed using a semi-quantitative Food Frequency Questionnaire. High-carbohydrate intake was defined as &gt; 275&#xa0;g/day and high-fat intake as &gt; 65&#xa0;g/day. Gender-stratified logistic regression analyses examined associations between dietary patterns and obesity, adjusted for age and total energy intake. Within-gender prevalence of overweight/obesity was 78.3% (65/83) in men and 64.6% (192/297) in women. However, women constituted 74.7% of the overweight/obese group due to their higher representation in the sample (78.2%). High-carbohydrate intake was associated with obesity in women (OR = 2.43, 95% CI 1.47–4.04, <i>p</i> = 0.001) but not men. High-fat intake was associated with obesity in both men (OR = 3.42, 95% CI 1.13–10.28, <i>p</i> = 0.032) and women (OR = 1.67, 95% CI 1.02–2.73, <i>p</i> = 0.048). In women, high-carbohydrate intake was also associated with elevated triglycerides (OR = 2.48, <i>p</i> = 0.021) and increased BMI (OR = 2.49, <i>p</i> &lt; 0.001). Both high-carbohydrate and high-fat dietary patterns showed gender-specific associations with obesity in Thai adults. These exploratory findings suggest the need for gender-specific dietary recommendations, particularly carbohydrate control for women at risk of central obesity, requiring confirmation through longitudinal studies.</p><p><i>Trial registration</i>: TCTR20240815001. </p>