A systematic review, meta-analysis, and meta-regression of the impact of diurnal intermittent fasting during Ramadan on body weight in healthy subjects aged 16 years and above

• Published in: European journal of nutrition Vol. 59; no. 6; pp. 2291 - 2316
• Main Authors: Jahrami, Haitham A., Alsibai, Joud, Clark, Cain C. T., Faris, Mo’ez Al-Islam E.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2020; Springer Nature B.V
• Subjects: Body size; Body weight; Chemistry; Chemistry and Materials Science; confidence interval; Diurnal; Fasting; Meta-analysis; Nutrition; Obesity; Ramadan; regression analysis; Review; Systematic review; Obesity; Body weight; Diurnal intermittent fasting; Systematic review; Ramadan; Caloric restriction; Meta-analysis
• ISSN: 1436-6207; 1436-6215; 1436-6215
• DOI: 10.1007/s00394-020-02216-1

Purpose Studies on the effect of Ramadan diurnal intermittent fasting (RDIF) on body weight have yielded conflicting results. Therefore, we conducted a systematic review and meta-analysis to estimate the effect size of body weight changes in healthy, non-athletic Muslims practicing Ramadan fasting, and to assess the effect of covariates such as age, sex, fasting time duration, season, and country, using subgroup analysis, and meta-regression. Covariate adjustments were performed to explain the variability of weight change in response to Ramadan fasting. Methods CINAHL, Cochrane, EBSCOhost, EMBASE, Google Scholar, ProQuest Medical, PubMed/MEDLINE, ScienceDirect, Scopus, and Web of Science databases were searched from date of inception in 1950 to the end of August 2019. Results Eighty-five studies, conducted in 25 countries during 1982–2019, were identified. RDIF yielded a significant, but small reduction in body weight ( K  = 85, number of subjects, N  = 4176 (aged 16–80 years), Hedges’ g =− 0.360, 95% confidence interval (CI) − 0.405 to − 0.315, I 2  = 45.6%), this effect size translates into difference in means of − 1.022 kg (95% CI − 1.164 kg to − 0.880 kg). Regression analysis for moderator covariates revealed that fasting time (min/day) is a significant ( P  < 0.05) moderator for weight change at the end of Ramadan, while age and sex are not. Variable effects for the season and country were found. Conclusion RDIF may confer a significant small reduction in body weight in non-athletic healthy people aged 16 years and above, directly associated with fasting time and variably correlated with the season, and country.