Effects of Ramadan and Non-ramadan Intermittent Fasting on Body Composition: A Systematic Review and Meta-Analysis

Abstract

Intermittent fasting (IF) has gained popularity for body-composition improvement purposes. The aim of this systematic review and meta-analysis was to summarize the effects of Ramadan vs. non-Ramadan IF on parameters of body composition. We conducted a comprehensive search of peer-reviewed articles in three electronic databases: PubMed, Scopus, and Web of Science (published until May 2020). Studies were selected if they included samples of adults (≥18 years), had an experimental or observational design, investigated any type of IF and included body composition outcomes. Meta-analytical procedures were conducted when feasible. Sixty-six articles met the eligibility criteria. We found that non-Ramadan IF is effective for decreasing body weight (−0.341 (95% CI [−0.584, −0.098], p = 0.006), body mass index (−0.699, 95% CI [−1.05, −0.347], p < 0.001), and absolute fat mass (−0.447, 95% CI [−0.673, −0.221], p < 0.001). When contrasting pre- post-intervention data on fat-free mass between treatments and controls, group-differences were non-significant (p > 0.05). Conversely, we observed a significant increase in fat-free mass when comparing pre- to post-intervention in a within design fashion (0.306, 95% CI [0.133, 0.48], p = 0.001). Finally, despite being accompanied by dehydration, Ramadan IF is effective in decreasing body weight (−0.353; 95% CI [−0.651, −0.054], p = 0.02) and relative fat mass (−0.533; 95% CI [−1.025, −0.04], p = 0.034). Ramadan IF seems to implicate some beneficial adaptations in weight management, although non-Ramadan IF appears to be more effective in improving overall body composition.

Impact of Ramadan Fasting on Dietary Intakes Among Healthy Adults: A Year-Round Comparative Study

“…The lack of significant change in total caloric intake reported in the current work is in line with the findings of many studies in different parts of the world (23,58,(69)(70)(71)(72). Accordingly, a few previous studies proposed Ramadan as a variant of intermittent fasting (73). In fact, the comparable total energy and macronutrient intakes during Ramadan and regular days in this study represents one of the distinguishing features of an intermittent fasting regimen (74).…”

The Window Matters: A Systematic Review of Time Restricted Eating Strategies in Relation to Cortisol and Melatonin Secretion

“…However, there is insufficient evidence as to whether the changes in circadian rhythmicity of cortisol during Ramadan lead to these consequences [ 63 , 64 , 65 , 66 ]. For example, a recent systematic review and meta-analysis found that Ramadan TRF is effective in decreasing body weight (−0.353; 95% CI [−0.651, −0.054], p = 0.02) and relative fat mass (−0.533; 95% CI [−1.025, −0.04], p = 0.034) [ 67 ], and another meta-analysis found positive effects on cardiometabolic risk factors such as triglycerides, total cholesterol, LDL, VLDL, HR, DBP, and increases HDL [ 68 ]. Given the unclear link between the disruption of cortisol rhythmicity and cardiometabolic outcomes in Ramadan studies, further work should be done to understand whether there is any direct impact related to the circadian rhythm.…”

Effect of Intermittent Fasting (18/6) on Energy Expenditure, Nutritional Status, and Body Composition in Healthy Adults

“…It has also been reported that adaptation may be better in this type of diet than other dietary practices [ 6 ]. Nowadays, the ultimate goal of most intermittent fasting regimens is to improve body composition [ 7 ]. However, losing weight is not typically targeted in the intermittent fasting type of Ramadan.…”

“…A meta-analysis study reported that the average body weight loss during the Ramadan period could be 1.24 kg and 0.76 kg body weight gain within 2 weeks following Ramadan [ 12 ]. In a recent meta-analysis, Ramadan intermittent fasting is effective in decreasing body weight (−0.353; 95% CI [−0.651, −0.054]) and relative fat mass (−0.533; 95% CI [−1.025, −0.04]) [ 7 ].…”