The relationship between night eating behavior, gastrointestinal symptoms, and psychological well-being: insights from a cross-sectional study in Türkiye

Abstract

Background

This cross-sectional study aimed to address the gap in understanding how night eating behavior impacts gastrointestinal health and psychological well-being in adult populations.

Method

This descriptive and cross-sectional study was conducted with 1372 adults aged 19–65 between September 2023 and November 2023. The research data were collected with the help of a web-based survey form (Google form) created by the researchers using the snowball sampling method. The demographic characteristics (sex, age, education level, marital status, income status), eating behaviors (number of main meals and snacks), and anthropometric measurements (body weight and height). Gastrointestinal symptoms observed in individuals were evaluated with the Gastrointestinal Symptom Rating Scale. The Night Eating Questionnaire (NEQ) was used to quantify the severity of night eating syndrome, and The Psychological Well-Being Scale was used to measure psychological well-being. All analyses were performed using the Statistical Package for the Social Sciences (version 27.0) software.

Results

A statistically significant negative correlation was found between the Psychological Well-Being Scale total score and Gastrointestinal Symptom Rating Scale subdimensions (r=-0.067, r=-0.067, r=-0.109, r=-0.068, r=-0.129, respectively). Also, a statistically significant negative correlation was found between the Psychological Well-Being Scale total score and the Night Eating Questionnaire total score (r=-0.287) (p < 0.05).

Conclusion

This study found a relationship between night eating syndrome, psychological well-being, and gastrointestinal symptoms. Nutritional strategies for night eating syndrome, an eating disorder, may have important consequences on the psychological well-being of individuals with night eating. Our study highlights the significant relationships between night eating behavior, gastrointestinal symptoms, and psychological well-being, suggesting that night eating may contribute to both physical and mental health challenges.

Plain language summary

This study explored how night eating behavior affects gastrointestinal health and psychological well-being in adults aged 19 to 65. Data were collected from 1372 participants through an online survey, which included information about their socio-demographic characteristics, night eating behavior, psychological well-being, and gastrointestinal symptoms. The findings revealed that night eating syndrome is linked to more gastrointestinal symptoms and lower psychological well-being. These results suggest that night eating behavior might contribute to both physical and mental health problems. Developing nutritional strategies to address night eating syndrome could have positive impacts on both psychological well-being and gastrointestinal health.

Introduction

Emerging research highlights the intricate communication between the brain and the gut, known as the brain-gut axis, which plays a crucial role in regulating physical and mental health [1–3]. This connection is evident in the role serotonin plays not only as a neurotransmitter that regulates mood but also as a key factor in gastrointestinal motility, underscoring the bidirectional relationship between the digestive and nervous systems [4]. Moreover, the stimulation of the vagus nerve, a critical pathway in brain-gut communication, has been reported to improve mood and psychological well-being by modulating digestive functions and stress responses [5]. The vagus nerve connects many different organs including the heart, gut, liver, and lungs and the primary nerve supports the parasympathetic nervous system. This nerve is an ideal candidate for well-being, given its regulatory role over the sympathetic nervous system, hypothalamic-pituitary-adrenal axis, immune system, and gut-brain axis [6]. Critically, heart rate variability reflects an index of the functioning of the vagus nerve, and can be used as a target for tracking the impact of wellbeing-related interventions including for example, a healthy lifestyle, heart rate variability, mind-body techniques, compassion-focused therapy, loving-kindness meditation and nature-based wellbeing interventions [6, 7]. One of the factors affecting psychological well-being is gastrointestinal diseases. Studies investigating the impact of gastrointestinal disorders on psychological well-being have consistently reported that these conditions can significantly disrupt daily life. Individuals with gastrointestinal disorders often experience limitations in daily activities, emotional distress such as fear and shame, lack of concentration, anxiety, and depression [8–11]. Given that eating patterns and behaviors are crucial determinants of gastrointestinal health [12, 13], the potential link between gastrointestinal disorders, eating behavior, and psychological well-being warrants closer investigation [14, 15].

Recent publications have also explored the relationship between eating behavior and psychological well-being. For example, Tuncer and Duman [16] observed that individuals with mental health disorders exhibit higher emotional eating scores, which are correlated with night eating behaviors, emphasizing the interplay between eating patterns and mental health [17, 18]. Psychological health is crucial in maintaining well-being and behavioral models for healthy living have an important place in the sustainability of mental health [19]. In addition to genetics, there are also biological and environmental factors that can affect psychological health. In this context, recent studies have begun to focus on these factors especially those on diet [20–22]. Although research on the effects of diet on psychological health started by examining nutrient deficiencies, the interest continues to increase in eating behavior [23]. A recent meta-analysis revealed that a Mediterranean dietary pattern may positively affect mental health [24]. In addition, a positive association between skipping meals and depression has been reported [25]. Also, anxiety was associated with eating behavior regardless of nutritional status [26]. So, according to these studies, it seems that eating behavior and mental health are related [27].

Night-eating syndrome (NES) is a condition characterized by a combination of morning loss of appetite (anorexia), excessive evening food intake (hyperphagia), and nocturnal awakenings accompanied by eating episodes [28]. This disorder is closely linked to depressed mood and has a reported prevalence of approximately 1.5% in the general population, although rates are significantly higher in psychiatric populations [29]. Studies suggest that between 22.4% and 25% of patients seeking psychiatric treatment meet the criteria for NES [30–32]. Additionally, night eating has been shown to affect the intestinal microbiota, leading to potential metabolic disruptions [33]. A comprehensive review emphasizes that people with NES often experience gastrointestinal distress alongside sleep disruptions and mood disorders, making the relationship between these systems complex and multifaceted [34]. On the other hand, it is reported that the body’s natural digestive processes are disrupted by late-night food consumption, leading to potential gastrointestinal complications [35].

Despite the increasing understanding of NES, its impacts on both psychological health and gastrointestinal functioning require further exploration to establish a more cohesive argument. There is a notable gap in the literature regarding the relationships between night eating behaviors, gastrointestinal symptoms, and psychological well-being. This study aims to address this gap by examining whether: (i) night eating behavior is related to psychological well-being, (ii) night eating behavior is related to gastrointestinal symptoms, and (iii) gastrointestinal symptoms are related to psychological well-being in adults. Furthermore, the study will explore the role of income status, and the number of snacks consumed in shaping these relationships, providing a more comprehensive understanding of the factors influencing night eating behavior.

Methods

This study was conducted with 1372 adults aged 19–65 between September 2023 and November 2023. The research data were collected with the help of a web-based survey form (Google form) created by the researchers using the snowball sampling method. Survey data were collected via social media tools Twitter, Facebook, WhatsApp and Instagram. The inclusion criteria for the study are as follows: individuals aged between 19 and 65 years, with internet access, who ticked the “I agree to participate in this study voluntarily” tab at the beginning of the online survey, and who completed the survey in its entirety were included in the study. Individuals diagnosed with eating behavior disorders, gastrointestinal system diseases, and psychiatric diseases were not included in the study. Individuals answered the survey questions in about 15 min.

Ethical consideration

Before the study’s inception, ethical approval with decision number 2023 − 302 dated 22.08.2023 was taken from the University of Health Sciences Gülhane Scientific Research Ethics Committee. The Declaration of Helsinki was followed in all aspects of the study’s procedures.

Materials

The demographic characteristics, eating behaviors (number of main meals and snacks), anthropometric measurements, gastrointestinal symptoms, night eating, and psychological well-being were collected via the questionnaire form.

Anthropometric measurements

Anthropometric data (height and body weight) were obtained using the individuals’ self-reports. The questionnaire form provided instructions on how to take anthropometric measures. The body mass index (BMI) value was calculated by dividing the body weight by the square of the height. Body mass index values were categorized as underweight (< 18.50 kg/m²), normal (18.50–24.99 kg/m²), overweight (25.0–29.99 kg/m²), and obese (≥ 30.0 kg/m²) [30].

Gastrointestinal symptoms

Gastrointestinal symptoms observed in individuals were evaluated with the Gastrointestinal Symptom Rating Scale (GSRS) [36]. The GSRS consists of 15 questions and is a 7-point Likert type. The scale has five subdimensions: diarrhea, indigestion, constipation, abdominal pain, and reflux. The patient is asked in the GSRS how they have been feeling over the past week concerning GI issues. The severity of the symptoms increases with higher scores. Turan et al. [37] conducted a validity and reliability study of the scale in 2017, reporting the Cronbach’s α coefficient of 0.82 for all items. In this study, the Cronbach’s alpha value of the scale was found to be 0.86.

Night eating behavior

Night Eating Questionnaire (NEQ) was used to quantify the severity of night eating syndrome in individuals [38]. The scale’s Turkish validity and reliability study was conducted by Atasoy et al. [39] in 2014. The scale comprises of 14 questions, and the items except the 7th item in the scale are scored between 0 and 4 with a five-point Likert-type measurement. Item 13 is not included in the scoring. The scale yields a total score ranging from 0 to 52. Higher scores indicate increased severity of night eating syndrome. The Cronbach α value of the scale was 0.69.

Psychological well-being

The Psychological Well-Being Scale was used to measure psychological well-being [40]. There are eight questions on the scale, and the items on the scale are scored between 1 and 7 with a seven-point Likert-type measurement. The scale yields a total score ranging from 8 to 56. Higher scores indicate that the individual has better psychological strength. The Turkish version reliability and validity study of the scale was conducted by Telef [41] in 2013. The Cronbach’s α coefficient of the scale was 0.87.

Statistical analysis

Post-hoc power analysis was conducted using G*Power (version 3.1.9.7, Universitat Düsseldorf, Düsseldorf, Germany), with the effect size calculated for the correlation between the total scores of the Night Eating Questionnaire and Psychological Well-Being Scale. Based on the analysis (r = 0,287) the statistical power (1-β) was found to be 99% for the statistical significance of 2-sided alpha of 5%.

All statistical analyses were conducted using the Statistical Package for the Social Sciences software, version 27.0. Descriptive statistics such as mean, standard deviation, number and percentage were used in the analysis of data on the general characteristics of the participants and are given in Table 1. Distribution analysis of the data was performed using the histogram, coefficient of variation ratio, skewness, kurtosis, and Kolmogorov–Smirnov tests. Relationships between night eating, gastrointestinal symptoms, and psychological well-being were assessed using Pearson correlation coefficients in Table 2. The effects of different factors on night eating, gastrointestinal symptoms, and psychological well-being were investigated using a multivariate linear regression model. All variables except age and number of snacks were found to be normally distributed. The non-normally distributed variables were logarithmically transformed to more nearly resemble the normal distribution for the linear regression analysis. In the regression model in Table 3, the dependent variable was the Night Eating Questionnaire total score, while the independent variables were age, income status, the Psychological Well-Being Scale total score, and number of snacks. In the regression models in Table 4, the dependent variable was the Gastrointestinal Symptom Rating Scale Subdimensions’ scores (Abdominal pain, reflux, diarrhea, indigestion, constipation, respectively) and the independent variables were sex-marital status and the Night Eating Questionnaire total score. In the regression model in Table 5, the dependent variable was the Psychological Well-Being Scale total score, while the independent variables were education level, income status, number of snacks, and the Night Eating Questionnaire total score. The explanatory power and accuracy of the independent variables in predicting the Night Eating Questionnaire total score, Gastrointestinal Symptom Rating Scale subdimensions’ scores, and Psychological Well-Being Scale total score were investigated using Pearson correlation coefficient (R) and coefficient of determination (R²). The independent variables included in the multiple linear regression analysis were determined using the Backward method. In addition, the potential multiple correlation between the independent variables in the multiple linear regression analysis was determined by examining the Variance Inflation Factor (VIF). For this study, the Variance Inflation Factor value being less than 4 indicated that there was no multiple correlation between the independent variables, and the necessary condition for establishing the regression model was provided. Statistical significance was evaluated at p < 0.05, p < 0.001, and 95% confidence intervals.

Table 1.

General characteristics of individuals (n = 1373)

Variables	N (%)
Sex
Female Male	958 (69.8) 414 (30.2)
Education level
Primary school Middle school High school University Master’s degree/ Doctorate	54 (3.9) 37 (2.7) 239 (17.4) 975 (71.1) 67 (4.9)
BMI classification
Underweight (< 18.50 kg/m2) Normal (18.50–24.99 kg/m2) Overweight (25.00–29.99 kg/m2) Obese (≥ 30.0 kg/m2)	127 (9.3) 761 (55.5) 347 (25.3) 137 (10.0)
Marital status
Married Unmarried	444 (32.4) 928 (67.6)
Income status
Income more than expenses Income equal to expenses Income less than expenses	271 (19.8) 723 (52.7) 378 (27.6)
Number of main meals
One meal Two meals Three meals	30 (2.2) 710 (51.7) 632 (46.1)
Age (years)	28.4 ± 11.82
BMI (kg/m 2 )	24.3 ± 11.34
Number of main meals	2.4 ± 0.53
Number of snacks	1.3 ± 0.96
Gastrointestinal Symptom Rating Scale Subdimensions
Abdominal pain	6.2 ± 3.77
Reflux	3.9 ± 2.80
Diarrhea	5.1 ± 3.44
Indigestion	9.1 ± 5.32
Constipation	5.7 ± 4.03
Night Eating Questionnaire total score	16.8 ± 6.01
Psychological Well-Being Scale total score	40.7 ± 11.90

Table 2.

The Relationship between the gastrointestinal Symptom Rating Scale, the Night Eating Questionnaire, and the Psychological Well-being scale

	Gastrointestinal Symptom Rating Scale					Night Eating Questionnaire	Psychological Well-Being Scale
	Abdominal pain	Reflux	Diarrhea	Indigestion	Constipation	Total score	Total score
GSRS
Abdominal pain	-	0.612**	0.533**	0.704**	0.509**	0.156**	-0.067*
Reflux		-	0.440**	0.533**	0.414**	0.145**	-0.067*
Diarrhea			-	0.583**	0.551**	0.145**	-0.109**
Indigestion				-	0.600**	0.138**	-0.068*
Constipation					-	0.160**	-0.129**
NEQ
Total score						-	-0.287**
PWS
Total score							-

*p < 0.05, **p < 0.001

Table 3.

Linear regression model for night eating prediction

	Night Eating Questionnaire total score
Model	Beta	t	p -value
Age (years)	-0.085	-3.297	0.001*
Income status	-0.079	-3.028	0.003*
Psychological Well-Being Scale total score	-0.255	-9.936	< 0.001**
Number of snacks	0.170	6.664	< 0.001**
		R2 = 0.289; p < 0.001**

Variable values: Income Status (Income less than expenses = 1, Income equal to expenses = 2, Income more than expenses = 3), *p < 0.05, **p < 0.001

Table 4.

Linear regression model for gastrointestinal symptom prediction

	Gastrointestinal Symptom Rating Scale Subdimensions
	Abdominal pain			Reflux			Diarrhea			Indigestion			Constipation
Model	Beta	t	p	Beta	t	p	Beta	t	p	Beta	t	p	Beta	t	p
Sex	-0.166	-6.344	< 0.001**	-0.052	-1.951	0.047*	-0.082	-3.059	0.002*	-0.116	-4.396	< 0.001**	-0.153	-5.816	< 0.001**
Marital status	-0.085	-3.252	0.001*	-0.057	-2.117	0.034*	-0.067	-2.851	0.010*	-0.054	-2.089	0.028*	-0.052	-1.951	0.047*
Night Eating Questionnaire total score	0.168	6.408	< 0.001**	0.165	6.182	< 0.001**	0.141	5.269	< 0.001**	0.159	5.983	< 0.001**	0.167	6.341	< 0.001**
	R2 = 0.256; p < 0.001**			R2 = 0.177; p < 0.001**			R2 = 0.163; p < 0.001**			R2 = 0.200; p < 0.001**			R2 = 0.228; p < 0.001**

Variable values: Sex (Male = 1, Female = 0); Marital status (Unmarried = 1, Married = 0), *p < 0.05, **p < 0.001

Table 5.

Linear regression model for psychological well-being prediction

	Psychological Well-Being Scale total score
Model	Beta	t	p-value
Education level	0.051	1.962	0.048*
Income status	0.077	1.962	0.048*
Number of snacks	0.091	2.947	0.003*
Night Eating Questionnaire total score	-0.267	-10.085	< 0.001**
		R2 = 0.290; p < 0.001**

Variable values: Education level (Primary school graduate = 1, Middle school graduate = 2, High school graduate = 3, University graduate = 4, Master’s and Doctorate graduates = 5), (Income Status (Income less than expenses = 1, Income equal to expenses = 2, Income more than expenses = 3), *p < 0.05, **p < 0.001

Results

The general characteristics of individuals are presented in Table 1. The mean age of the individuals was 28.4 ± 11.82 years. The mean number of main meals of the individuals was 2.4 ± 0.53, and the mean number of snacks was 1.3 ± 0.96. The mean Night Eating Questionnaire total score was 16.8 ± 6.01, and the mean the Psychological Well-Being Scale total score was 40.7 ± 11.90. More than half of the individuals (55.5%) were in the normal range according to BMI classification. 71.1% of individuals were university graduates. 32.4% of individuals were married. 27.6% of individuals had income less than their expenses.

The relationship between the Gastrointestinal Symptom Rating Scale, the Night Eating Questionnaire, and the Psychological Well-Being Scale is given in Table 2. A statistically significant positive correlation was found between the Gastrointestinal Symptom Rating Scale subdimensions and the Night Eating Questionnaire total score (r = 0.156, r = 0.145, r = 0145, r = 0.138, r = 0.160, respectively). A statistically significant negative correlation was found between the Psychological Well-Being Scale total score and Gastrointestinal Symptom Rating Scale subdimensions (r=-0.067, r=-0.067, r=-0.109, r=-0.068, r=-0.129, respectively). Also, a statistically significant negative correlation was found between the Psychological Well-Being Scale total score and the Night Eating Questionnaire total score (r=-0.287) (p < 0.05).

Linear regression analysis for night eating prediction is given in Table 3. When assessing factors influencing the Night Eating Questionnaire total score through linear regression analysis, the model demonstrated significance (R² = 0.289; p < 0.001). Approximately 28.9% of the variance in the total score of the Night Eating Questionnaire can be explained by the model. Age (β=-0.085, p = 0.001), income status (β=-0.079, p = 0.003), and the Psychological Well-Being Scale total score (β=-0.255, p < 0.001) had significant negative effects on the Night Eating Questionnaire total score. The number of snacks (β = 0.170, p < 0.001), had a significant positive effect on the Night Eating Questionnaire total score.

When evaluating factors influencing the subdimensions of the Gastrointestinal Symptom Rating Scale using linear regression analysis, the model was found to be significant. 25.6% of the variance in the abdominal pain score, 17.7% of the variance in the reflux score, 16.3% of the variance in the diarrhea score, 20.0% of the variance in the indigestion score, and 22.8% of the variance in the constipation score can be explained by the model. Sex and marital status had significant negative effects on all subdimension scores of the Gastrointestinal Symptom Rating Scale. The total score of the Night Eating Questionnaire had a significant negative effect on all subdimension scores of the Gastrointestinal Symptom Rating Scale (p < 0.05) (Table 4).

The results of the linear regression analysis predicting psychological well-being are presented in Table 5. When evaluating factors influencing the Psychological Well-Being Scale total score, the model showed significance (R²=0.290; p < 0.001). Approximately 29.0% of the variance in the total score of the Psychological Well-Being Scale can be explained by the model. Education level (β = 0.051, p = 0.048), income status (β = 0.077, p = 0.048), and number of snacks (β = 0.091, p = 0.003) had significant positive effects on the total score of the Psychological Well-Being Scale. The Night Eating Questionnaire total score (β=-0.267, p < 0.001) had a significant negative effect on the Psychological Well-Being Scale total score.

Discussion

In this investigation, we aimed to explore the relationships between night eating, gastrointestinal symptoms, and psychological well-being in adults. To our knowledge, this is the first study to examine these relationships collectively in a sample of adults. This research fills a critical gap in the literature by examining how night eating behavior affects both gastrointestinal symptoms and psychological well-being, areas that have been predominantly studied in isolation. While prior studies have focused on the physical or psychological impacts of night eating in isolation, our work uniquely considers the interplay between gastrointestinal health and mental well-being. It is thought that nocturnal eating behavior may influence gastrointestinal symptoms that are related to psychological well-being. Key findings from our study indicate that: (i) there was a strong negative relationship between psychological well-being and night eating; (ii) there was a positive correlation between night eating and gastrointestinal symptoms; (iii) there was a positive relationship between the number of snacks and psychological well-being; and (iv) gastrointestinal symptoms and psychological well-being were negatively related. (v) age, income status, psychological well-being, and the number of snacks affected night eating behavior (vi) education level, income status, number of snacks, and Night Eating Questionnaire total score affected psychological well-being.

Our findings contribute to the growing body of literature showing a link between night eating behavior and psychological well-being. It has been reported that night eating behavior, which is a risk factor for obesity, is positively correlated with BMI and affects BMI independently of age, sleep duration, and sleep timing [42]. Similarly, Berg et al. have shown that night eating is significantly associated with obesity [43]. A cross-sectional study indicated that individuals who consumed ≥ 33% of their total energy intake in the evening had a higher risk of becoming obese [44]. Thus, night eating behavior is associated with obesity and increases the risk of metabolic syndrome and diabetes [45]. However, studies have also linked night eating behavior to mental health issues, especially in psychiatric populations [46–49]. Our study, in contrast, suggests that night eating behavior influences psychological well-being beyond clinical or psychiatric populations. In this context, our study extends these findings by examining the psychological impact of night eating beyond metabolic outcomes, underscoring the importance of addressing both mental and physical health in individuals with night eating behavior.

We found that night eating behavior was significantly associated with psychological well-being, a finding supported by previous studies that have linked night eating syndrome to depressive symptoms and emotional distress [46, 49, 50]. One study on university students reported a positive association between stress and night eating, suggesting that coping mechanisms may influence this relationship [51]. Additionally, Geliebter et al. reported higher depressive status in individuals with night eating syndrome [52]. Our results, consistent with these findings, suggest that night eating behavior is not only related to mental health but may also contribute to poor psychological well-being. This relationship could be mediated by several factors, including sleep disturbances and emotional dysregulation, which are known to impact both eating behaviors and mental health. However, the directionality of this relationship remains unclear: it is possible that night-eating behavior negatively affects well-being, or that individuals with poor well-being are more prone to engage in night-eating behavior. Further research, including longitudinal and randomized-controlled studies, is necessary to clarify these mechanisms.

Next, our results indicate a strong positive correlation between night eating and gastrointestinal symptoms. Previous studies have mostly focused on eating disorders and their gastrointestinal effects [53–55], but our research highlights the broader relationship between general eating behavior, gastrointestinal distress, and psychological health. One possible explanation for this connection is the disruption of circadian rhythms caused by night eating, which can interfere with the gastrointestinal system’s natural functioning, leading to discomfort and distress. Fasting therapy, for example, has been reported to alleviate symptoms such as abdominal pain and diarrhea in individuals with irritable bowel syndrome [56], while low-fat, high-fiber diets have been shown to reduce gastrointestinal symptoms [57]. Our study adds to this literature by showing that night eating behavior, even outside of clinical eating disorders, may exacerbate gastrointestinal symptoms, which, in turn, could negatively impact psychological well-being. Furthermore, our regression analysis confirmed that night eating is one of the factors influencing gastrointestinal symptoms, a finding supported by Melchior et al., who associated gastrointestinal disorders with anxiety in individuals with eating disorders [58].

Given the interconnectedness of the digestive system and the brain, particularly through the brain-gut axis, it is plausible that gastrointestinal symptoms not only cause physical discomfort but also exacerbate psychological distress, thereby creating a feedback loop that perpetuates both gastrointestinal issues and poor psychological well-being. Nutritional interventions targeting night eating behavior could improve not only metabolic health but also psychological well-being and gastrointestinal function. Given the bidirectional relationships between these variables, comprehensive treatment plans should consider both the mental and physical health aspects of night eating syndrome. Clinicians could implement strategies such as meal timing interventions, stress management techniques, and dietary modifications to mitigate the negative effects of night eating behavior.

In this study, other factors affecting the occurrence of gastrointestinal symptoms were marital status and gender. We observed that gastrointestinal symptoms were higher in married participants and women. The finding that women experience more gastrointestinal symptoms compared to men is supported by existing literature. Many studies about gastrointestinal symptoms have shown that women are more likely to report conditions such as irritable bowel syndrome and other gastrointestinal disorders, similar to our findings [59, 60]. In addition, a study with a large population showed higher gastrointestinal symptoms in women [61]. Higher rates of anxiety and depression in women could be significant contributors to gastrointestinal disorders [62]. The gut-brain axis, a bidirectional communication system between the central nervous system and the enteric nervous system, is influenced by psychological stress, which can exacerbate GI symptoms such as bloating, pain, and irregular bowel movements [63]. On the other hand, the relationship between marital status and gastrointestinal status is another finding of our research. However, Nilsson and Ohlsson reported no association between marital status and gastrointestinal symptoms [64]. Similarly, a study on irritable bowel syndrome patients reported that marital status was not associated with gastrointestinal symptoms [65]. Marriage can affect gastrointestinal health in complex ways, primarily because of the behavioral, psychological, and lifestyle changes associated with the marital environment. Often associated with emotional support, marital life can also increase stress levels due to relationship dynamics, conflicts, and lifestyle changes (changing dietary habits, decreased physical activity levels, etc.), which can contribute to gastrointestinal problems [66, 67].

In this study, it was observed that age, income status, psychological well-being, and the number of snacks affected night eating behavior (Table 1). Age was evaluated as having a negative effect on night eating behavior. The fact that young adults tend to eat more often at night suggests that this may be related to various lifestyle and psychological factors. Circadian rhythm changes with age. Young individuals often experience a delayed sleep phase, which can lead to longer wakefulness at night, leading to night eating behavior [68, 69]. In addition, psychological factors such as stress and emotional regulation affect young people more, and they may tend to eat emotionally, especially late at night, in order to cope with these emotional states [68]. Overall, the relationship between decreasing age and increasing night eating behavior among adults may be attributed to a combination of circadian rhythm changes, emotional eating habits, and lifestyle factors.

In this study, one of the factors that positively affect night eating behavior was determined as the number of snacks. Some mechanisms explain the relationship between meal frequency and night eating behavior. One of these is that individuals who consume fewer meals throughout the day generally feel hungrier and cravings in the evening. This increase in hunger can lead to an increased likelihood of night eating as the body tries to compensate for long periods of hunger [70]. It is also known that increased meal frequency helps regulate appetite-related hormones such as ghrelin and leptin. When meal frequency is low, ghrelin levels tend to increase, which can stimulate hunger and encourage late-night eating [71]. Moreover, psychological factors play an important role in this relationship. It has been reported that individuals who follow a higher frequency of eating tend to exhibit better self-regulation and control over their eating habits. This improved self-regulation may lead to a decrease in the frequency of impulsive eating behaviors during the night [72]. In this study, contrary to the literature, it was determined that as the number of snacks increased, night eating behavior also increased. This may be since individuals considered night snacks as snacks. Since meals consumed at night are also considered snacks, it is expected that night eating behavior increases in parallel with the increase in the number of snacks. The fact that the number of snacks during the day was not questioned separately may explain this situation and may be considered a limitation of the study.

In this study, it was found that education level, income status, number of snacks, and Night Eating Questionnaire total score were associated with psychological well-being (Table 3). Education level and income status have a positive effect relationship with on psychological well-being. This finding is consistent with the literature. More highly educated individuals report better health, lower rates of impairment and disability, lower risk of premature death, and lower rates of depression. There are several implications supporting the positive relationship between education level and an individual’s mental health [73]. According to the Fundamental Cause Theory, education is a fundamental cause of health because it provides access to health-enhancing resources such as higher income, better health care, access to healthier foods, and a healthier lifestyle [74]. Human Capital Theory conceptualizes education as an investment that provides returns to the individual, including more talent, skills, and resources that can produce better health [75]. For all these reasons, there is a positive relationship between education, income level, and psychological well-being, and our results support this result with the regression analyses we conducted.

In this study, it was observed that in addition to education level and income status, snack frequency also affects increased psychological well-being. Similar to the results of this study, there is data suggesting that higher meal frequency can positively affect mood and mental health [76]. There are several possible reasons for this. Increased meal frequency is generally associated with better metabolic health, which may contribute to better psychological outcomes [77]. Increased meal frequency can potentially lead to decreased feelings of anxiety and depression by regulating appetite and increasing satiety [78].

Our study has several strengths, including its focus on the relationships between night eating, gastrointestinal symptoms, and psychological well-being. However, there are limitations that need to be acknowledged. First, self-reported anthropometric data limited our ability to assess the role of BMI in these relationships. Second, we did not collect detailed dietary records, which would have provided insight into diet quality and its potential impact on psychological well-being. Third, the relatively young and highly educated sample limits the generalizability of our findings to the broader Turkish population. Lastly, the lack of a causal link due to its cross-sectional nature is a limitation of the study. Future studies should address these limitations by incorporating objective measures of dietary intake, using a more representative sample, and investigating the long-term effects of night eating on both psychological and gastrointestinal health.

In conclusion, this study provides evidence of the relationship between night eating, gastrointestinal symptoms, and psychological well-being in adults. Our findings suggest that addressing night eating behavior could have meaningful implications for both mental health and gastrointestinal function. Future research should explore these relationships in more diverse populations and longitudinal studies to assess causal associations to inform targeted nutritional interventions as potential treatments for individuals with night eating behavior.

Author contributions

Conceptualization: EME; ÖMÇ; ZEM, Data Curation: EME; ÖMÇ; ZEM, Formal Analysis: EME; ÖMÇ; ZEM, Supervision: EME; ÖMÇ, Validation: EME; ÖMÇ; ZEM, Data Analysis: ÖMÇ, Writing-Original Draft: EME; ÖMÇ; ZEM, Review & Editing: EME; ÖMÇ; ZEM.

Funding

This research received no specific grant from any funding agency, commercial or non-profit sectors.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethical approval and consent to participate

Before the study’s inception, ethical approval with the decision number 2023 − 302 dated 22.08.2023 was taken from the University of Health Sciences Gülhane Scientific Research Ethics Committee. The Declaration of Helsinki was followed in all aspects of the study’s procedures. Consent was obtained from individuals at the beginning of the web-based survey form stating that they volunteered to participate in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.