Objective: Studies regarding health effects of religious fasting have been increased during the last decade. Our aim was to investigate the impact of adherence to the periodic Christian Orthodox Church (COC) fasting on nutrient intake, body composition, and risk factors for metabolic syndrome (MetS). Methods: Four-hundred individuals aged 42.6 ± 17.0 years participated in this cross-sectional study. Two-hundred subjects followed the COC fasting since childhood or at least the last twelve consecutive years, and two-hundred subjects did not follow the COC fasting regimes or any other restrictive dietary pattern. Socioeconomic data, lifestyle habits, and physical activity data were collected. Nutritional assessment was performed via two 24 h recalls and a food frequency questionnaire. Anthropometric data and biochemical parameters were also measured. Results: Fasters had a significantly lower daily intake of calories (1547 vs. 1662 kcals,p= 0.009), protein (52 vs. 59 g,p= 0.001), fat (82 vs. 89 g,p= 0.012), and cholesterol (147 vs. 178 g,p= 0.001) compared with non-fasters. Furthermore, fasters reported a healthier way of living, with lower rates of smoking and alcohol consumption (p< 0.001 and 0.002, respectively). Insulin and magnesium levels were significantly higher, whereas levels of urea, transaminases, glucose, and phosphorus were significantly lower, as was DBP in fasters versus non-fasters. Furthermore, MetS prevalence was non-significantly higher in non-faster compared with fasters. Conclusion: During a non-fasting period, individuals following the COC fasting recommendations reported lower intake of calories, protein, fat, and cholesterol compared with non-fasters. Fasters tended to have a healthier lifestyle pattern and a lower risk for MetS versus non-fasters. Some biochemical parameters also significantly differed between the two study groups. Further research is warranted to establish the long-term clinical impact of these findings.