Changes in energy and macronutrient intakes during Ramadan fasting: a systematic review, meta-analysis, and meta-regression

Abstract

Context Ramadan fasting (RF) is associated with various physiological and metabolic changes among fasting Muslims. However, it remains unclear whether these effects are attributable to changes in meal timing or changes in dietary energy and macronutrient intakes. Furthermore, the literature on the associations between RF, meal timing, and energy and macronutrient intakes is inconclusive. Objectives This systematic review aimed to estimate the effect sizes of RF on energy and macronutrient intakes (carbohydrates, protein, fats, dietary fiber, and water) and determine the effect of different moderators on the examined outcomes. Data Sources The Cochrane, CINAHL, EMBASE, EBSCOhost, Google Scholar, PubMed/MEDLINE, ProQuest Medical, Scopus, ScienceDirect, and Web of Science databases were searched from inception to January 31, 2022. Data Extraction The studies that assessed energy, carbohydrate, protein, fat, fiber, and water intakes pre- and post-fasting were extracted. Data Analysis Of the 4776 identified studies, 85 relevant studies (n = 4594 participants aged 9–85 y) were selected. The effect sizes for the studied variables were as follows: energy (number of studies [K] = 80, n = 3343 participants; mean difference [MD]: −142.45; 95% confidence interval [CI]: −215.19, −69.71), carbohydrates (K = 75, n = 3111; MD: −23.90; 95% CI: −36.42, −11.38), protein (K = 74, n = 3108; MD: −4.21; 95% CI: −7.34, −1.07), fats (K = 73, n = 3058; MD: −2.03; 95% CI: −5.73, 1.67), fiber (K = 16, n = 1198; MD: 0.47; 95% CI: −1.44, 2.39), and water (K = 17, n = 772; MD: −350.80; 95% CI: −618.09, 83.50). Subgroup analyses showed age significantly moderated the 6 dietary outcomes, and physical activity significantly moderated water intake. There were significant reductions in energy, carbohydrate, and protein intakes during RF. Conclusions The change in meal timing rather than quantitative dietary intake may explain various physiological and health effects associated with RF.

The impact of intermittent fasting during Ramadan on psychomotor and cognitive skills in adolescent athletes

“…Our results showed that RIF was not associated related to variations in total daily caloric intake at different timepoints, which is consistent with previous studies among female athletes ( 5 , 18 , 52 , 53 ). Similarly, Abdelrahim et al ( 54 ) indicated that the different physiological and health effects associated with RIF may be explained by changes in meal timing rather than by changes in quantitative dietary intake. Nevertheless, Jahrami et al ( 41 ) suggested that RIF might be linked to a significant, small decrease in body weight in young, healthy, non-athletic individuals.…”

The dietary changes during Ramadan and their impact on anthropometry, blood pressure, and metabolic profile

“…Likewise, reported studies are inconsistent on the intake of macronutrients, including fat ( 3 , 14 , 19 ), carbohydrates ( 13 , 17 , 19 ), cholesterol ( 13 , 14 ), and protein ( 3 , 19 ). Recently, Abdelrahim et al conducted a meta-analysis and reported a reduction in total energy intake, carbohydrates, protein and water intakes and no change in fat or protein intakes during Ramadan ( 4 ). The previous observational studies often focused on specific ethnic groups or nationalities, potentially skewing the results.…”

“…Ramadan intermittent fasting (RIF) is associated with a sudden drastic change in the dietary behavior of observers. Although observing RIF does not dictate restriction on calorie intake or type of food, previous studies showed that it incurs significant changes in eating habits, patterns, duration, frequency of meals and intakes of energy and macronutrients (1)(2)(3)(4). Observers feast after sunset (Iftar) and eat another lighter meal before dusk (Suhur) (5) and more often in groups of family and friends (6).…”