Islamic Ramadan is a 29-30 day fast in which food, fluids, medications, drugs and smoking are prohibited during the daylight hours which can be extended between 13 and 18 h · day(-1) depending on the geographical location and season. The majority of health-specific findings related to Ramadan fasting are mixed. The likely causes for these heterogeneous findings lie in the amount of daily time of fasting, number of subjects who smoke, take oral medications, and/or receive intravenous fluids, in the type of food and eating habits and in changes in lifestyle. During Ramadan fasting, glucose homeostasis is maintained by meals taken during night time before dawn and by liver glycogen stores. Changes in serum lipids are variable and depend on the quality and quantity of food intake, physical activity and exercise, and changes in body weight. Compliant, well-controlled type II diabetics may observe Ramadan fasting, but fasting is not recommended for type I, noncompliant, poorly controlled and pregnant diabetics. There are no adverse effects of Ramadan fasting on respiratory and cardiovascular systems, haematologic profile, endocrine, and neuropsychiatric functions.
Conclusions: Although Ramadan fasting is safe for all healthy individuals, those with various diseases should consult their physicians and follow medical and scientific recommendations.