Between 2011-16, the holy month of Ramadan occurred in the summer. It is a solemn month, during which Muslims do not eat or drink between sunrise and sunset and contemplate their spiritual being.

But have you ever considered how hard it must be not to drink in 40C to 50C (104F to 122F) weather? Or to put in a full day's work with no food or drink for about 14 hours? Or to be ravenously hungry after sunset, and eat a huge meal, and then go promptly to bed because you have to wake up well before sunrise to eat the allowed breakfast, which has to keep your energy up until after sunset?

A brief review of the literature around the implications of fasting does not, for a variety of practical reasons, offer any definitive conclusions, but makes some interesting observations:

• Researchers looked at 137 Jordanian adults fasting during Ramadan, dividing them into three groups: overweight, normal weight (controls), and underweight. All three groups had a substantial reduction in weight, with the greatest loss in the overweight group. "Medical Implications of Controlled Fasting," J R Soc Med 1998;91:260-163.
• Since fasters also abstain from medications during daylight hours, toxic effects were found particularly in older patients who took their medications once in the day, rather than at the prescribed intervals. "Medical Implications of Controlled Fasting," J R Soc Med 1998;91:260-163.
• A five-year study of patients in a Turkish hospital showed a significant increase in patients treated for peptic ulcer complications during Ramadan. "Medical Implications of Controlled Fasting," J R Soc Med 1998;91:260-163.
• Among athletes, there is a tendency to delay training sessions until after sunset, following the end of the fast, which results in sleep loss. "Effects of Ramadan on Physical Performance: Chronobiological Considerations," Br J Sports Med 2010;44:509-515.
• In patients with type II diabetes that fast, the most commonly reported symptom was excessive thirst. "Practices of Arab American Patients with Type 2 Diabetes Mellitus During Ramadan," J Pharm Pract, 2011 Apr;24(2):211-5.
• When healthy pregnant women fast during Ramadan, there is no significant adverse effect on intrauterine fetal development or on the fetus's health. "Effect of Fasting During Ramadan on Fetal Development and Maternal Health," J Obstet Gynaecol Res 2008 Aug;34(4):494-8.
• "Comparisons between different studies of Ramadan fasting are difficult due to several confounding variables. Daily fasting time is highly dependent upon the time of the seasonal year that Ramadan occurs as well as the location's latitudinal distance from the equator. The percentage of subjects who smoke, consume oral medications, and/or receive intravenous fluids can greatly affect a study's findings, because these activities are forbidden during the daylight hours of Ramadan." "The Impact of Religious Fasting on Human Health," Nutr J 2010; 9:57.
• A study of patients before/during Ramadan showed that the time of onset of an acute stroke varies, with the "Before Ramadan" group having a higher frequency of onset between 0600h-1200h, and the "During Ramadan" group having a higher frequency of onset between 1200h and 1800h. "Circadian Rhythm of Stroke Onset During the Month of Ramadan," Acta Neurol Scand 2010 Aug;122(2):97-101.

I was very religious when I was a young girl. During Lent, I would give up a favourite food, not eat between meals, and fast totally on Good Friday. I remember feeling very please with myself — even more so because my brothers laughed at me.

Helen Ziegler