Recommended guideline for designing and interpreting of Ramadan fasting studies in medical research

Ramadan fasting is specific intermittent fasting comprising significant changes in routine lifestyle pattern and may affect body homeostasis and metabolism. In spite of several studies conducted on the effects of Ramadan fasting on various aspects of health and disease, because of heterogeneity in methodology and procedures (sometimes inevitable), a comprehensive concluding for reliable results as in most conditions is impossible. Based on basic studies and those have been conducted in this field, this paper suggests a checklist contains, as far as possible, important factors to be considered in designing, interpreting and comparing the results of Ramadan fasting studies. Accordingly, circadian rhythm, season/latitude sensitivity, serum osmolarity and, lifestyle changes (including dietary intakes, physical activity, sleep quality and duration, smoking and, etc.) may be of great importance. Also, a close definition of the number of fasting days and it consecutively or alternatively must be presented with reference to sex. Appropriate time points for blood/urine sampling would be varied case by case.