Background Metabolic dysfunction-associated steatotic liver disease (MASLD) increases cardiovascular risk, but the vascular benefits of reducing hepatic triglycerides remain unclear. Aim To determine whether short-term diet-induced reductions in hepatic triglycerides improve arterial stiffness and endothelial function. Methods In a two-week, two-arm pre-post dietary intervention trial, adults with MASLD or elevated risk were assigned to either a low-carbohydrate (<30 g carbohydrate/day, n = 24) or low-calorie diet (~1,200−1,500 kcal/day, n = 23). Hepatic triglyceride content was assessed using proton density fat fraction magnetic resonance imaging. Vascular assessments included arterial stiffness as assessed by pulse wave velocity (PWV), and endothelial function via brachial artery flow-mediated dilation (FMD). The Framingham Risk Score (FRS) was evaluated pre- and post-intervention. Results At baseline, 31 of 47 participants had MASLD. In the total sample, hepatic triglyceride content decreased by 15% relative to baseline (p < 0.001), with no significant differences between the two diet groups. Brachial-ankle PWV decreased by 41 cm/s (p = 0.001). FRS decreased (p < 0.001) and FMD (p = 0.030) increased by ~1.0% in absolute terms. Reductions in hepatic triglyceride content were positively correlated with changes in heart rate at rest (r = 0.49, p = 0.001), even after the adjustment of age and body weight change (r = 0.35, p = 0.021). Conclusions Vascular function improvements and cardiovascular risk reductions occurred along with hepatic triglyceride reduction following a two-week dietary intervention. Changes in hepatic triglyceride content were positively correlated with the corresponding changes in heart rate but not with measures of vascular function. (ClinicalTrials.gov, NCT05216796).