ABSTRACT
Background: Fasting during the month of Ramadan for Muslims is a unique metabolic model that includes abstinence from food and fluid intake during the period from dawn to sunset as well as a reduction in meal frequency and alterations in the sleep-wakefulness cycle. Leptin, neuropeptide-Y and insulin are thought to play an important role in long-term regulation of caloric intake and energy expenditure. However, the long-term changes and interactions between these factors during this pattern of fasting are not known
Subjects and Methods: The study was conducted on 46 healthy female volunteers [age, 22 +/- 2 years; BMI, 25.3 +/- 0.7 kg/m2]. Anthropometrical measurements, estimation of body fat and fasting serum levels of neuropeptide Y, leptin, insulin and glucose were estimated at baseline [day 1], days 14 and 28 of the month of Ramadan and 2 weeks after Ramadan
Results: Baseline serum levels of leptin correlated positively with body fat [r=0.87, P=0.0002]. Serum leptin levels exhibited a significant increase by approximately 41% and neuropeptide-Y levels were decreased by 30.4% throughout the month of Ramadan. In addition, a significant correlation [r=0.63, P=0.0001] was found between changes in serum leptin and serum insulin. However, changes in serum neuropeptide-Y levels did not correlate with those of leptin or insulin
Conclusion: Long-term fasting with interrupted nocturnal eating is associated with significant elevations in serum leptin and insulin and reduction in serum neuropeptide-Y. The changes in serum leptin are likely mediated through insulin. However, changes in neuropeptide-Y appears to be mediated independently of leptin or insulin during this type of fasting