What are the effects of Ramadan fasting on activity, energy expenditure?
An association exists between Ramadan fasting and reduced activity and sleeping time, suggests a study, adding that no significant change is seen in resting metabolic rate (RMR) and total energy expenditure (TEE).
“Reported weight changes with Ramadan in other studies are more likely to be due to differences in food intake,” the investigators said.
Ramadan fasting did not induce any change in RMR (mean±SD, 1,365.7±230.2 vs 1,362.9±273.6 kcal/d for Ramadan and post-Ramadan, respectively; p=0.713; n=29). However, there was greater RMR in the first week of Ramadan compared with subsequent weeks after controlling for the effects of age, sex and body weight.
The total number of steps walked during Ramadan were significantly lower (n=11; p=0.001). There was also a reduction in overall sleeping time, while different sleeping patterns were observed. In addition, no significant difference was seen in TEE between Ramadan and post-Ramadan (mean, 2,224±433.7 vs 2,121.0±718.5 kcal/d, respectively; p=0.7695; n=10).
To investigate the impact of Ramadan fasting on RMR, TEE and activity, 29 healthy nonobese volunteers (16 women) fasting during Ramadan were recruited. Indirect calorimetry was used to measure RMR. Activity (n=11; five women) and TEE (n=10; five women) in free-living conditions were measured using accelerometers and the doubly labelled water technique, respectively, in subgroups of participants.
Bioelectrical impedance was used to measure body composition. The investigators repeated these measurements after a washout period of 1–2 months after Ramadan. Nonparametric tests were used for comparative statistics.
“Fasting during the month of Ramadan entails abstinence from eating and drinking between dawn and sunset and a major shift in meal times and patterns with associated changes in several hormones and circadian rhythms,” the investigators said.