INTRODUCTION: Experimental studies have demonstrated that obesity increases salt sensitivity, defined as the blood pressure (BP) response to salt intake; however, its relevance within real-world lifestyle modification settings remains uncertain. This study aimed to investigate the cross-sectional and longitudinal associations between daily salt intake and BP according to obesity status. METHODS: This observational study analyzed data from adult men with hypertension who participated in a remote lifestyle modification program. Daily salt intake was estimated from urinary sodium excretion using a validated self-monitoring device and expressed as equivalent sodium chloride (NaCl) (g/day), and home systolic blood pressure (SBP) was recorded. A cross-sectional analysis compared SBP among the tertiles of salt intake at baseline. Longitudinal analysis was used to compare SBP reduction among the tertiles of salt intake reduction over 3 months. These analyses were adjusted for potential confounders and stratified by obesity, defined as body mass index ≥ 25 kg/m2. RESULTS: A total of 1095 participants were included (median age, 57 years; obese, 67.2%). At baseline, higher daily salt intake was associated with higher SBP in the obesity group (lowest tertile, estimated mean; 130.7 mmHg [95% confidence interval 129.2 to 132.3]; middle tertile, 132.2 [130.7 to 133.8]; highest tertile, 133.2 [131.6 to 134.7]; p = 0.028), but not in the nonobese group (p = 0.174). After 3 months, a greater reduction in salt intake was associated with a greater SBP decrease in the obese group (lowest tertile, estimated mean -2.5 [-3.5 to -1.4] mmHg; middle tertile, -3.5 [-4.5 to -2.4] mmHg; highest tertile, -5.2 [-6.3 to -4.1] mmHg; p < 0.001) but not in the nonobese group (p = 0.335). CONCLUSION: These findings suggest that, in real-world lifestyle modification settings, changes in salt intake are associated with changes in BP among adult men with obesity, highlighting the clinical relevance of salt sensitivity for tailored BP management.