View of The Comparison of Anthropometry and Cognitive Function Before and During Ramadhan Fasting among Overweight and Obese Adults in Kuala Nerus, Terengganu, Malaysia

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https://doi.org/10.37231/ajmb.2023.1.S.683 https://journal.unisza.edu.my/ajmb

Comparison of Anthropometry and Cognitive Function Before and During Ramadhan Fasting among Overweight and Obese Adults in Kuala Nerus,

Terengganu, Malaysia

Mahirah Mohd Arin, Noor Sharmimi Atirah Padzi, Che Suhaili Che Taha*

School of Nutrition and Dietetics, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, 21300 Kuala Terengganu, Malaysia.

Corresponding author: [email protected]

Received: 1^st August 2023 Accepted: 8^th November 2023 Published: 24^th December 2023

Abstract

Ramadhan fasting is one of the five pillars in Islam. During these 29-30 days of holistic and spiritual days, Muslims abstain from drinking and eating from dawn to sunset. This alteration of dietary behavior could affect not only on anthropometry but also cognitive function. This prospective observational study aimed to determine the effect of Ramadhan fasting on anthropometry and cognitive function and its correlation between overweight and obese adult populations. This study recruited adults aged between 19 to 65 years old with a BMI of ≥23.0 kg/m2 live in Kuala Nerus. Sociodemographic, anthropometry, and cognitive function data were assessed twice; Before Ramadhan (two weeks prior to Ramadhan) and During Ramadhan (week 3 and 4 during Ramadhan). Anthropometry data including body weight, height, body mass index (BMI), waist circumference, body fat percentage, muscle mass, and total body water were measured using a weighing scale, stadiometer, measuring tape, and bioelectrical impedance analysis (BIA) while the cognitive function was assessed using the Malay Version of the Auditory Verbal Learning Test (MAVLT), Trail Making Test (TMT) A and B, and Stroop Task. A total of 146 participants were recruited with old 54.8% were male while 45.2% were female. The mean age of participants was 42.6±19.4 years.

Analysis on the anthropometry data showed that weight, BMI, waist circumference, and body fat percentage were significantly reduced during Ramadhan with p<0.001. Meanwhile, the cognitive function data showed that the completion time for Stroop Congruent and Incongruent Test, and TMT B were significantly reduced during Ramadhan with p<0.001 signifying a better executive performance. The MAVLT learning and recognition scores were significantly increased during Ramadhan (p<0.001) indicating an improvement in memory. The correlational analysis showed the negative correlation between the changes in waist circumference and MAVLT learning during Ramadhan (p=0.031) indicating that reduced waist circumference results in increased MAVLT learning score during Ramadhan. This study’s limitation includes the number of participants that did not reach the required sample size. In conclusion, the current study showed the significant potential of Ramadhan fasting to improve anthropometry outcomes and cognitive function among overweight and obese adults.

Keywords

Ramadhan fasting, Anthropometry, Cognitive function, Overweight, Obese

Asian Journal of Medicine and Biomedicine

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Introduction

Ramadhan fasting is a mandatory Muslim practice throughout the ninth month of the Islamic calendar based on the lunar cycle. During the month of Ramadhan, Muslims are required to refrain from eating, drinking, smoking, engaging in sexual activity, and taking medication during the daytime hours of Ramadhan from dawn to sunset.¹ They are also encouraged to perform various sunnah practices such as Tarawih prayer. During Ramadhan, Muslims normally eat two simple meals, one before dawn (Suhur) and one after sundown (Iftar). The changes in dietary behavior during Ramadhan could alter their dietary intake. Some people might eat less and some also tend to overeat during the night time after iftar. Other components such as physical activity, cognitive performance and quality of life might also significantly change during Ramadhan.

Overweight and obesity refers to an abnormal or excessive build-up of fat that poses health risks, which usually classified using Body Mass Index (BMI).² Based on the Malaysian National Health and Morbidity Survey (2019), half of the Malaysian population is overweight and obese suggesting an alarming issues to tackle at national level. To combat this, several prevention initiatives and weight-reduction plans were implemented in Malaysia to decrease the prevalence of overweight and obesity. In addition, the practice of fasting especially during Ramadhan has also become more popular as one of strategies to lose weight.

Muslims frequently modify their lifestyles by fasting during Ramadhan to promote weight loss. The abstention from food and drink consumption during Ramadhan leads to a reduction in meal frequency that eventually causes lower caloric intake.³ During Ramadhan fasting, the body fat percentage, visceral fat level and subcutaneous fat were decreased due to the reserve fat in the body being used as energy resulting from starvation during fasting.⁴ This leads to the improvement in anthropometry status that includes the reduction in weight and body fat.

However, the effect of Ramadhan fasting towards cognitive function remains unclear due to the inconsistency and contradictions of a bunch of findings. A study has indicated a positive impact of Ramadhan fasting on cognitive function that involved the improvement in psychomotor function, processing speed, and attention.⁵ Another study reported that during Ramadhan, it has been claimed that vigilance, memory, and sustained attention may be impaired and the start of Ramadhan fasting has also been associated with increased reaction time.⁶ However, the effect of Ramadhan fasting on cognitive function among the overweight and obese population still remains unclear due to the lack of evidence. Thus, this study was conducted to investigate how Ramadhan fasting could affect the anthropometry data and cognitive function among the overweight and obese population.

Materials and Methods Study design

This prospective observational study was conducted from March 2023 until April 2023 in Kuala Nerus, Terengganu, Malaysia.

Ethical statement

Ethical approval was obtained prior to this study data collection from the University of Sultan Zainal Abidin Human Research and Ethics Committee (UHREC) [UniSZA/UHREC/2022/465].

Study population

The study population includes the population of the community that lives in Kuala Nerus, a district located in Terengganu, Malaysia. The study participants included overweight and obese adults between the age of 19 to 65 years old with BMI ≥ 23.0 kg/m2. The participants only involved Muslims who practice Ramadhan fasting. This study excluded pregnant and breastfeeding women, individuals with physical and mental disabilities, and individuals under weight loss programme. The calculated sample size was 162 samples after assuming 10% drop out. 146 participants were included in this study and each participation were voluntary, and prior consent was given. 146 of them have completed the anthropometry assessments, but

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only 137 of them managed to complete both anthropometry and cognitive function assessments. However, during Ramadhan, only 115 of them managed to attend the second data collection, and only 97 participants have completed both anthropometry and cognitive function assessments. This study recorded 34%

dropout rate (N=97).

Variable and measurement

The variables measured in this study were anthropometry and cognitive function. The anthropometry measurements include body weight, height, Body Mass Index (BMI), waist circumference, body fat percentage, muscle mass, and total body water using a TANITA Body Composition Monitor, BC-541.

Meanwhile, the cognitive function parameters include the completion time and number of errors for Stroop Task and Trail Making Test (TMT) A and B, and the scores of the Malay Auditory Verbal Learning Test (MAVLT). The trail making test (TMT) is a quick and practical assessment of cognitive abilities, primarily working memory and attention which consists of two parts where participants were required to connect the circles in sequence.⁷Meanwhile, Stroop task was used to measure attention, processing speed, cognitive flexibility and working memory where participants were required to read words and colors in three different parts of questions which consisted of two Stroop congruent tests and one Stroop incongruent test.⁸ Then, MAVLT was used to test for verbal learning and memory of a person that consisted of 15 words that need to be presented to the participants for them to memorize and repeat the words as many as they can remember.⁹

Data collection

The data were collected twice, before and during Ramadhan. For ‘before Ramadhan’, the data were collected two weeks prior to Ramadhan fasting while for during Ramadhan, data were taken within the week three and four during Ramadhan month. After the first week of Ramadan, the majority of people's metabolic adaption tends to stabilize. Therefore, data were measured in the second half of the month, which was within week 3 to capture more obvious and stable metabolic alterations.

Anthropometry measurements

Participants were assessed using a body composition monitor bioelectrical impedance analysis (BIA) to measure their body weight (kg), BMI (kg/m²), body fat percentage (%), muscle mass (kg), and total body water (%), and used a stadiometer to measure their height (m) and BMI (kg/m²) and measuring tape to measure their waist circumference (cm).

Cognitive function assessments

Three cognitive tasks were administered to the participants which refers to The Stroop Task, Trail Making Test A and B, and the Malay Auditory Verbal Learning Test (MAVLT). In Stroop Task and TMT A and B, the participants were measured based on their completion time and number of errors, while for MAVLT, the participants were measured based on the scores for each component of MAVLT which include A1, A2, A3, A1-A3 (Total learning), B, A4, A5, and recall (recognition). Each cognitive function test assessed different domains of cognition. Stroop Task measured attention, processing speed, and working memory, TMT A &

B measured executive control, attention, and working memory, while MAVLT measured verbal learning, memory, and recognition.^7–9 The estimated amount of time required for each participant to complete all three cognitive function assessments was 15-20 minutes.

Results

The sociodemographic characteristics of the participants were examined using descriptive statistics. A paired-samples t-test and the Wilcoxon signed-ranks test were used for parametric and non-parametric testing, respectively, to examine the changes in the participants’ anthropometry and cognitive function over two time periods. Meanwhile, the correlation between the two variables was analyzed using Spearman’s rho correlation test for non-parametric variables and Pearson’s r correlation for parametric variables.

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Sociodemographic data

The mean age of the respondents was 42.6±19.4 years old. Majority of the respondents were male (54.8%), while the other 45.2% were female. All 146 respondents were Malay (100.0%). For the marital status, majority of the respondents (51.4%) were married, followed by 43.2% of respondents were single, and 5.5% were widow/widower. The educational level of the respondents was majority at tertiary educational level (61.0%), followed by secondary education level (34.9%), and primary (4.1%). The income level data shows that most of the respondents (93.2%) were considered as B40 (<RM4850) which include both respondents with no income or low income, while 6.8% of the respondents were from M40 (RM4851- RM10,970) and none of them come from T20 (>RM10,971). Table 1 shows the sociodemographic characteristics of respondents.

Anthropometry data before and during Ramadhan fasting

The comparison of anthropometry measurements before Ramadhan (BR) and during Ramadhan (DR) is shown in Table 2. Most of the anthropometry parameters showed significant changes during Ramadhan.

The body weight showed significant reduction among the respondents during Ramadhan (M=68.7 kg, SD=10.4) as compared to before Ramadhan (M=71.0 kg, SD=10.5) with the reduction of -2.3 kg which was statistically significant, (t (115) =-20.28, p<0.001). Body mass index (BMI) was also significantly reduced by 0.9 unit during Ramadhan (M=26.9 kg/m², SD=3.3) as compared to before Ramadhan (M=27.8 kg/m², SD=3.3) and was statistically significant (t (115) =-20.56, p<0.001). Similarly, waist circumference measurement during Ramadhan (M=90.0 cm, SD=12.3), was significantly reduced by 3.2 cm compared to before Ramadhan (M=93.2 cm, SD=12.4) and was statistically significant (t (115) =-11.62, p<0.001). For body fat percentage, it was lower during Ramadhan (M=30.5 %, SD=8.2) as compared to before Ramadhan (M=32.1 %, SD=7.9) where the reduction is -1.6% and statistically significant (t (115) =-10.31, p<0.001).

However, the muscle mass was reduced during Ramadhan (M=45.3 kg, SD=8.7) which is slightly lower than before Ramadhan (M=45.7 kg, SD=8.8). The muscle mass was reduced by -0.4 kg and is statistically significant (t (115) =-3.14, p=0.002). Meanwhile, no significant difference of total body water was observed during Ramadhan.

Level of cognitive function before and during Ramadhan fasting

Table 3 shows the comparison of cognitive function assessment before and during Ramadhan which expressed in mean±SD and median (min-max) as assessed by Stroop Task, TMT A and B, and Malay Version of Auditory Verbal Learning Test (MAVLT). All data showed significant change during Ramadhan except for the number of errors for TMT A. The completion time of Stroop congruent task 1 during Ramadhan is improved by 1.6 seconds (M=20.1, SD=5.2) as compared to before Ramadhan (M=21.7, SD=5.9) and was statistically significant, (t (97) =-6.67, p<0.001). Meanwhile, for the number of errors of Stroop congruent task 1, there was an improvement during Ramadhan (Mdn=0.0, Min-Max=0-0) compared to before Ramadhan (Mdn=0.0, Min-Max=0-1), with a median improvement of 0.0. This improvement was found to be statistically significant (Z=-2.24, p=0.025). For Stroop congruent task 2, there was an improvement in completion time during Ramadhan (M=30.9, SD=7.1) as compared to before Ramadhan (M=34.3, SD=8.1).

The improvement was -3.4 s, which was statistically significant (t (97) =-8.87, p<0.001). Significant improvement was also observed in the number of errors during Ramadhan (Mdn=0.0, Min-Max=0-2) compared to before Ramadhan (Mdn=0.0, Min-Max=0-5), with median improvement of 0.0, and statistically significant (Z=-4.25, p<0.001). Then, for Stroop incongruent task 3, there was an improvement in its completion time during Ramadhan (M=56.1, SD=16.5) compared to before Ramadhan (M=60.9, SD=17.6).

The improvement was by -4.9 seconds which was statistically significant (t (97) =-7.63, p<0.001). The number of errors also showed an improvement during Ramadhan (Mdn=0.0, Min-Max=0-6) as compared to before Ramadhan (Mdn=1.0, Min-Max=0-9). It was improved by -1.0 which was statistically significant (Z=-3.91, p<0.001).

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For the Trail Making Test A, the completion time for TMT A showed a significant increment during Ramadhan (M=41.7, SD=11.5) as compared to before Ramadhan (M=29.6, SD=11.3) suggested a decline in processing speed. However, no significant changes of accuracy for TMT A were observed. For TMT B, a significant improvement in both completion time and number of errors were observed. The completion time was improved by -7.5 seconds during Ramadhan (M=48.6, SD=11.2) as compared to before Ramadhan (M=56.2, SD=15.7), which was statistically significant (t (97) =-8.93, p<0.001). The number of errors was improved during Ramadhan (Mdn=0.0, Min-Max=0-3) as compared to before Ramadhan (Mdn=0.0, Min- Max=0-5). The median improvement was 0.0, demonstrating a statistically significant decrease in errors (Z=-4.24, p<0.001).

All results of Malay Version of Auditory Verbal Learning Test (MAVLT) that include A1, A2, A3, A1-A3, B, A4, A5, and Recall scores showed significant improvements during Ramadhan. During Ramadhan, there was a significant increase in scores for A1, with an improvement of 1.9 points (M=7.9, SD=1.9), compared to before Ramadhan (M=6.0, SD=1.9) (t (97) = 11.51, p<0.001). A2 was improved by 1.5 points during Ramadhan (M=9.8, SD=2.1) compared to before Ramadhan (M=8.2, SD=2.0) and it was statistically significant (t (97) =11.30, p<0.001). A3 was also improved during Ramadhan (M=11.4, SD=2.1) as compared to before Ramadhan (M=9.8, SD=2.3) and it was significantly improved by 1.5 points (t (97)

=11.23, p<0.001). Following the improvement in A1, A2 and A3 scores, the total of A1 to A3 scores that indicate the MAVLT total learning was also improved during Ramadhan (M=29.0, SD=5.5) compared to before Ramadhan (M=24.0, SD=5.5). It was improved by 5.0 points and statistically significant (t (97)

=15.52, p<0.001). The score for B which from the second list of MAVLT was also improved during Ramadhan (M=5.7, SD=1.6) as compared to before Ramadhan (M=4.6, SD=1.6), where it was significantly improved by 1.1 (t (97) =7.12, p<0.001). A4 demonstrated a significant improvement of 1.5 during Ramadhan (M=9.5, SD=2.4) compared to before Ramadhan (M=8.0, SD=2.5). This improvement was also found to be statistically significant (t (97) =9.53, p<0.001). Then, the improvement of A5 is by 1.7, as compared for during Ramadhan (M=10.0, SD=2.6) and before Ramadhan (M=8.2, SD=2.6). Last but not least, the recall scores of MAVLT also showed improvement during Ramadhan (M=28.0, SD=1.8) as compared to before Ramadhan (M=26.2, SD=2.7). It was improved by 1.8, with a statistically significant improvement (t (97) =9.42, p<0.001).

The correlation between the changes in anthropometry and cognitive function

A Spearman’s rho correlational analysis was performed to assess the relationship between the changes of anthropometry data and changes in cognitive function. Table 4 shows the significant correlations that were found between the changes in anthropometry data and changes in cognitive tasks. Based on the correlation coefficient value, -0.76 to -1.00 was interpreted as strong negative correlation, -0.51 to -0.75 as good negative, -0.26 to -0.50 as fair negative, 0 as no correlation, 0.01 to 0.25 as poor positive, 0.26 to 0.50 as fair positive, 0.51 to 0.75 as good positive, and 0.76 to 1.00 as strong positive correlation. Significant correlations were found between changes in waist circumference and changes in MAVLT A3, changes in waist circumference and changes in MAVLT A1-A3 (MAVLT Learning), changes in muscle mass and changes in TMT A (Completion Time, s), changes in muscle mass and changes in MAVLT A2, changes in muscle mass and changes in MAVLT A1-A3 (MAVLT Learning), and between changes in muscle mass and changes in MAVLT A5.

Changes in waist circumference and changes in MAVLT A3 shows a fair negative correlation, which indicates the reduction in waist circumference results in the improvement of MAVLT A3 score during Ramadhan which is statistically significant (r=-0.28, p=0.006). A significant negative correlation (r=-0.22, p=0.031) was observed between changes in waist circumference and changes in MAVLT A1-A3 (MAVLT Learning). This indicates that the reduction in waist circumference resulting in the improvement of MAVLT learning score. The greatest correlation for changes in muscle mass was observed between changes in muscle mass and changes in MAVLT A2, where it shows a fair negative correlation which is statistically

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significant (r=-0.31, p=0.002). Next, the correlation between changes in muscle mass and changes in TMT A (Completion Time, s) was also significantly correlated with a poor negative correlation (r=-0.21, p=0.041). The correlation between changes in muscle mass and changes in MAVLT A1-A3 (MAVLT Learning) also demonstrated a poor negative correlation which is statistically significant (r=-0.21, p=0.044). Then, changes in muscle mass and changes in MAVLT A5 also have a poor negative correlation which is statistically significant (r=-0.20, p=0.049). All these significant correlation results indicates that the reduction in muscle mass during Ramadhan resulted in the improvement in MAVLT A2, MAVLT A1-A3 (MAVLT Learning) and MAVLT A5 scores, and the decline in TMT A (Completion Time, s).

Table 1: Sociodemographic characteristics of respondents (n=146)

Variables Frequency / Mean±SD Percentage (%)

Age (years) 42.6±19.4

Gender

Male 80 54.8

Female 66 45.2

Race

Malay 146 100.0

Chinese - -

Indian - -

Marital Status

Single 63 43.2

Married 75 51.4

Widow/Widower 8 5.5

Educational Level

Primary 6 4.1

Secondary 51 34.9

Tertiary 89 61.0

Income

B40 (≤RM4,849) 136 93.2

M40 (RM4,850 – RM10,959) 10 6.8

T20 (≥RM15,039) - -

Table 2: Comparison of anthropometry measurements before and during Ramadhan

Parameters Mean±SD Mean diff p-values

BR DR

Weight (kg) 71.0±10.5 68.7±10.4 -2.3 <0.001

Body Mass Index, BMI (kg/m²) 27.8±3.3 26.9±3.3 -0.9 <0.001

Waist Circumference (cm) 93.2±12.4 90.0±12.3 -3.2 <0.001

Body Fat Percentage (%) 32.1±7.9 30.5±8.2 -1.6 <0.001

Muscle Mass (kg) 45.7±8.8 45.3±8.7 -0.4 0.002

Total Body Water (%) 50.1±6.1 50.4±5.7 0.4 0.099

Paired-samples T-test, the significant value was p<0.05.

Note ─ BR = Before Ramadhan; DR = During Ramadhan

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Table 3: Comparison of cognitive assessment before and during Ramadhan

Parameters Mean±SD Mean diff p-values

BR DR

Stroop Congruent Task (1)

Completion Time (s) 21.7±5.9 20.1±5.2 -1.6 <0.001

**Number of errors 0.0(0–1) 0.0(0–0) 0.0 0.025

Stroop Congruent Task (2)

**Number of errors 0.0(0–5) 0.0(0–2) 0.0 <0.001

Stroop Incongruent Task (3)

**Number of errors 1.0(0–9) 0.0(0–6) -1.0 <0.001

Trail Making Test (TMT) A

Completion Time (s) 29.6±11.3 41.7±11.5 12.1 <0.001

**Number of errors 0.0(0–2) 0.0(0–1) 0.0 0.166

Trail Making Test (TMT) B

**Number of errors 0.0(0–5) 0.0(0–3) 0.0 <0.001

Malay Version Auditory Verbal Learning Test (MAVLT)

A1 6.0±1.9 7.9±1.9 1.9 <0.001

A2 8.2±2.0 9.8±2.1 1.5 <0.001

A3 9.8±2.3 11.4±2.1 1.5 <0.001

Total Learning (A1-A3) 24.0±5.5 29.0±5.5 5.0 <0.001

B 4.6±1.6 5.7±1.6 1.1 <0.001

A4 8.0±2.5 9.5±2.4 1.5 <0.001

A5 8.2±2.6 10.0±2.6 1,7 <0.001

Recall 26.2±2.7 28.0±1.8 1.8 <0.001

Paired-samples T-test, the significant value was p<0.05.

**Used Wilcoxon Signed Ranks Test

Table 4: The significant correlations between the changes in anthropometry and cognitive function parameters during Ramadhan

Anthropometry Parameters Cognitive Function Parameters

Correlation coefficient, r

p-value Changes in waist circumference

(cm)

Changes in MAVLT A3 -0.279 0.006

Changes in waist circumference (cm)

Changes in MAVLT A1 – A3 -0.219 0.031

Changes in muscle mass (kg) Changes in TMT A (Completion Time) (s)

-0.207 0.041

Changes in muscle mass (kg) Changes in MAVLT A2 -0.309 0.002 Changes in muscle mass (kg) Changes in MAVLT A1 – A3 -0.205 0.044 Changes in muscle mass (kg) Changes in MAVLT A5 -0.200 0.049 Spearman’s rho correlation, significant value was p<0.05.

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Discussion

The anthropometry measurement of human body is an important indicator of nutritional status, which in the overweight and obese adult population, anthropometry measurements such as body weight, and BMI should be monitored regularly with the effort of reducing body weight in order to achieve a healthy weight.

The month of Ramadhan have encouraged the Muslim individuals to restrict calorie intake during the daytime hours which led to the changes in the anthropometry status.

The body weight and BMI of the overweight and obese adult population was found to be significantly reduced during Ramadhan as compared to before Ramadhan, which indicated the improvement in those parameters. A study by Nachvak et al.,¹⁰ suggested that the reduction in body weight and BMI during Ramadhan is due to the negative energy balance that could results from the decreased food intake during the month of Ramadhan as they only have two main meals which include suhoor before the dawn, and iftar after the sunset. These body weight and BMI improvements could be supported by several studies,^10–13 but contradicted with a study by Al-Barha & Aljaloud.¹⁴

A significant reduction in body fat percentage during Ramadhan was also observed in this study, which could be related with the improvement of body weight and BMI. This finding was corresponded to a study by Nachvak et al.¹⁰ and contradicted with several studies.^12,14 The negative energy balance in the body during fasting leads the body adjusts to fasting by slowing down basal metabolism and using lipids more effectively, which could result in the decrease of fat in the body. According to Sanvictores et al.,¹⁵ the effect of fasting would firstly happen to the pancreas, where it causes the pancreas to excrete more glucagon in order to use the glycogen stores in the liver when the plasma glucose is low. Then, the body would continue to use adipose tissue and protein for energy when the glycogen stores in the liver have been used up. Since this present study is mainly focus on the overweight and obese individuals, this could be one of the reasons that caused the remarkable differences of the degree of improvement for body weight, BMI, and body fat percentage when comparing to other studies. According to Harder-Lauridsen et al.,¹⁶ in comparison to lean individuals, Ramadhan fasting may have a stronger effect on body composition in obese individuals. This finding was also found in other studies and a meta-analysis by Fernando et al.¹⁷ have discussed that it was due to the bigger glycogen stores in people with higher BMI.

In agreement with a study by Elias et al.,¹² a significant reduction in waist circumference during Ramadhan was recorded. Waist circumference is a well-established marker of visceral obesity and a risk factor for morbidity and mortality.¹⁸ According to a study by Schroder et al.,¹⁹ that studied on the effect of time- restricted feeding in weight loss, metabolic syndrome and cardiovascular risk in obese women, they found that waist circumference and body fat percentage showed a statistically significant positive correlation, where the reduction in waist circumference due to the time-restricted feeding was correlated with the reduction in body fat percentage. This could support the present study findings where there were significant reductions in both body fat percentage and waist circumference due to the practice of fasting during Ramadhan.

During Ramadhan, it was found that all parameters which were measured in this study to assess the level of cognitive function demonstrated significant changes compared to before Ramadhan, except for the number of errors for TMT A. All those significant changes have indicated the improvement in the cognitive performance during Ramadhan except for the completion time of TMT A. The shorter completion time and lesser errors made by participants in Stroop Task during Ramadhan showed a better executive function and accuracy. Stroop task is a type of neuropsychological test that can be used to measure cognitive domains that include attention, processing speed, cognitive flexibility, and working memory.²⁰ This indicates that Ramadhan fasting has brought changes to the overweight and obese adults’ population by improving their cognitive performance in terms of its attention, processing speed, cognitive flexibility and working memory measured by Stroop task. A study by Tuan Omar & Che Taha²¹ also marked the

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improvement in the completion time of Stroop task during Ramadhan when measured among the healthy adults. At the same time, the improvement in TMT B also indicated a better working memory, and the executive control. In agreement with these findings, a study by Iqbal et al.¹¹ also detected the improvement in the spatial working memory after Ramadhan fasting. Another study by Boujelbane et al.²² have also noted a significant improvement in cognitive attention in both of their active and sedentary groups. Meanwhile, better performance of executive function was only found at the active group.

Some studies have established that calorie restriction could enhance attention and cognitive performance during neuropsychological test batteries.²³ Due to the nature of the practice of fasting during Ramadhan usually related to calorie restriction due to the reduction of meal frequency, this could be one of the reasons why fasting could impact better cognitive performance. However, it was noted in several studies that fasting could negatively affect concentration and memory due to the reduction in glucose availability. When food is normally available, glucose serves as the brain's primary energy source, and the oxidation of carbohydrates uses practically all the oxygen available.²⁴ In the same study, they also found that metabolic alterations brought on by fasting may improve brain function in terms of improved cognitive function and enhanced neuroplasticity. Another study has found that fasting could have positive effects on the brain due to the metabolic switch that happens in the body during fasting where glucose is switched with the stored lipids as the primary energy source that leads to the metabolization of ketones that have signaling effects on the brain.²⁵ Other than that, better cognitive performance during Ramadhan fasting could also affected by the familiarity of the participants towards the test during the second data collection. These factors can be applied to justify the improvement of the MAVLT scores during Ramadhan since all components of MAVLT scores which include A1, A2, A3, A1-A3 (MAVLT Learning), A4, A5, and MAVLT recall showed significant improvements in the overweight and obese adults’ population during Ramadhan. The improvement in MAVLT scores mainly indicates the improvement in verbal learning, memory &

recognition. Most studies have noted that Ramadhan fasting could result in better memory function. A study by Boujebane et al.²² which investigate on the effect of Ramadhan diurnal intermittent fasting, have found that there were significant improvements in recognition memory and associative memory. Furthermore, other factors that could be the major reason for how Ramadhan could result to a better cognitive function was by the religious activities that were performed during Ramadhan itself. During the month of Ramadhan, Muslims were encouraged to increase their religious activities such as performing sunnah prayers, and reciting Al-Quran. A study by Amir et al.²⁶ have concluded that, individual who performed more religious activities during Ramadhan have improved their cognitive performance as measured using Montreal Cognitive Assessment (MoCA), which include the domain of cognitive attention, concentration, executive functions, memory language, visuoconstructional skills, conceptual thinking, calculation, and orientation. Regarding the decline in the cognitive performance measured by TMT A, the increase in the completion time during Ramadhan was probably due to the difference in the TMT A question sets. This could be due to the different sets of questions with different arrangements of numbers in the TMT provided during the first and second data collection which were randomly picked from the sets of questions that were already provided. The purpose was to avoid the practice effect on the participants during the second data collection that can make them solve the questions easily. Furthermore, participants also claimed that the TMT A of the second set was harder compared to the first set.

Significant correlations were found between changes in waist circumference and changes in MAVLT A3, changes in waist circumference and changes in MAVLT A1-A3 (MAVLT Learning), changes in muscle mass and changes in TMT A (Completion Time, s), changes in muscle mass and changes in MAVLT A2, changes in muscle mass and changes in MAVLT A1-A3 (MAVLT Learning), and between changes in muscle mass and changes in MAVLT A5. The only anthropometry parameters that involved in the significant correlations were waist circumference and muscle mass.

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Based on the data obtained, the changes in waist circumference is significantly negatively correlated with the changes in MAVLT A3 and MAVLT learning scores. Waist circumference is a typical anthropometric measurement which measures abdominal adiposity that was used as indicators of health and obesity. This study suggests that a reduction in waist circumference during Ramadhan as compared to before Ramadhan indicates an improvement in body fat which resulted in better cognitive performance. A study by Anand et al.²⁷ have concluded that higher central adiposity was generally linked to lower cognitive scores and their analysis also found that extra fat was the risk factor for lower cognitive performance. C-reactive protein (CRP) and interleukin-6 (IL-6) are circulating inflammatory markers that are heavily influenced by adipose tissue, which may highlight the link between obesity and dementia and cognitive decline.²⁸ Therefore, reduction in adiposity or body fat could help in maintaining or increasing cognitive performance.

Another significant correlation was found in the correlations that involved the changes in muscle mass. The changes in muscle mass are significantly negatively correlated with the changes of completion time of TMT A, MAVLT A2, MAVLT learning, and MAVLT A5 scores. These results demonstrated that the reduction in muscle mass is correlated with the improvement in the MAVLT A2, MAVLT learning, and MAVLT A5 scores.

The correlation with TMT A will not be discussed as the decline in TMT A results was mainly due to the harder question set received during Ramadhan. The correlation between muscle mass and cognition is still unclear, however, most of the previous studies would suggest that cognitive impairment is associated with the declined in muscle, not the improvement, or it usually could be no correlations at all between those two variables.

The study's strengths lie in its comprehensive cognitive function assessment tools, which covered various cognitive aspects and facilitated comparisons with prior research. Additionally, the anthropometry evaluation tools employed standardized measures for accurate results and were broadly applicable to a variety of demographics. However, significant limitations included a smaller-than-expected sample size, a relatively high dropout rate due to follow-up commitments, and a potential burden on participants during cognitive assessments, particularly with the lengthy memorization task.

Conclusion

In conclusion, this pre and post study have proven that Ramadhan fasting have positive significant impacts on anthropometry status and level of cognitive function. This study highlighted that Ramadhan fasting have improved body compositions of the overweight and obese adults’ population which include body weight, BMI, waist circumference, body fat percentage. Moreover, cognitive functions that include the domain of attention, executive function, processing speed, working memory, verbal learning and recognition were all positively affected by Ramadhan fasting. This study also found that the improvement in waist circumference was significantly correlated with the improvement of cognitive performance during Ramadhan. Therefore, this study can emphasize the great wisdom regarding the implementation of fasting in the month of Ramadhan. Every Muslim should understand the duties that need to be done and benefit from the practices that were encouraged in the month Ramadhan. Especially for the overweight and obese population, they should take the opportunity to improve their body composition during Ramadhan by performing fasting and other sunnah practices to ensure good well-being and health improvement.

Funding

The author(s) received no specific funding for this work.

Acknowledgements

We would like to express our gratitude to everyone who contributed towards this study data collection. We would also like to thank every participant’s time and contribution to this study’s data and the help from the research team members is much appreciated by the authors.

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Conflict of Interest Disclosure

The authors declare there is no conflict of interest.

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