Ramadan fasting entails abstinence from eating and drinking between dawn and sunset. During this month major changes in meal times and patterns, sleeping times and activity occur. Starvation is known to lead to a compensatory reduction in energy expenditure. However, the Ramadan fast is not synonymous with starvation as it involves intermittent periods of fasting followed by gorging. People who fast during Ramadan feel less energetic. However, little is known about the effects of this religious practice on energy metabolism. .