habit that inverts the normal human day-night routine for observance, can have deleterious health effects on sleep patterns and general health. Fasting in Ramadan has been shown to alter the sleep patterns and the associated hormone production. Statistical comparison of thousands of school children, part of whom was born without the month of Ramadan during pregnancy and part of whom where Ramadan coincided with the pregnancy, has revealed lower cognitive capability, and lower growth in adolescence if the mother observed Ramadan fasting during pregnancy. Children whose mothers fasted during Ramadan also have a higher incidence of several chronic diseases, e.g. Type 2 Diabetes. (see the ruling regarding fasting pregnant women) Fasting is one of the alternatives proved to reduce the DPP-4 level and activate the dipeptidyl peptidase-4 inhibitors and so, prevent osteoporosis. On the other hand, the circadian rhythm has a direct relationship with osteoporosis. This has been found by the biochemical markers, indicating that fasting at certain hours of the day, especially during those hours of the day which are recommended as part of the Muslim tradition (Islamic fasting), is very effective in reducing the effects of osteoporosis. The education departments of Berlin and the United Kingdom have tried to discourage students from fasting during Ramadan, as they claim that not eating or drinking can lead to concentration problems and bad grades. Ramadan fasting has also been associated with loss of workplace productivity by 35 to 50%. Many of the purported health benefits associated with Ramadan fasting only take into account abstinence from food while ignoring the lack of water intake, which can have a harmful impact even in healthy individuals. In many cultures, it is associated with heavy food and water intake during Suhur and Iftar times, which may do more harm than good. Ramadan fasting is safe for healthy people provided that overall food and water intake is adequate, but those with medical conditions should seek medical advice if they encounter health problems before or during fasting. The fasting period is usually associated with modest weight loss, but weight can return afterward. A review of the literature by an Iranian group suggested fasting during Ramadan might produce renal injury in patients with moderate (GFR <60 ml/min) or severe kidney disease but was not injurious to renal transplant patients with good function or most stone-forming patients. However, since sick and/or at-risk individuals are exempted from the obligation of