Comparative effects of intermittent fasting and calorie restriction on cardiovascular health in adults with overweight or obesity.

Cardiovascular disease (CVD) risk factors are a significant global health concern. Previous studies have demonstrated that lifestyle-based strategies such as 5:2 intermittent fasting (IF) and calorie restriction (CR) may improve blood pressure, lipid profiles, glycemic control, and cardiovascular risk scores. However, comparative evidence on their effects in real-world settings remains limited. This study aimed to compare the effects of 5:2 IF and CR on cardiovascular risk factors in overweight and obese adults. This longitudinal cohort study used data from the Iranian National Obesity Registry (IRNOR). A total of 82 participants were included (40 in the 5:2 IF group and 42 in the CR group). Participants followed either a 5:2 IF (500-600 kcal on fasting days, isocaloric on other days) or a daily CR approach (500-1000 kcal deficit). Cardiovascular risk factors including blood pressure indices, lipid profile components, glycemic markers, and CVD risk scores were compared between groups over three months. The mean age of participants was 35.55 ± 12.18 years (70.7% female). At the end of week 12, mean arterial pressure and rate-pressure product significantly decreased in both groups compared to that of the baseline (P < 0.05). The 5:2 IF group also experienced a significant decrease in serum triglyceride levels (P = 0.04). Additionally, at the end of the study, systolic blood pressure (123.78 ± 9.95 vs. 127.62 ± 12.16), pulse pressure (41.53 ± 6.76 vs. 46.51 ± 9.36), and the 30-year Framingham cardiovascular risk score for full CVD (19.17 ± 14.13 vs. 21.53 ± 15.10) and for hard CVD (10.31 ± 8.51 vs. 12.00 ± 9.88) were significantly lower in the 5:2 IF group compared to the amounts for the CR group (P < 0.05). However, no significant differences were observed in other metabolic parameters between the two groups (P > 0.05). Intermittent fasting regimen, particularly the 5:2 IF, may be associated with greater improvement in systolic blood pressure, pulse pressure, and the 30-year cardiovascular risk score over three months. Other metabolic outcomes were similar between the groups. Further studies are needed to confirm these findings.