BDI is a scale developed by Beck et al. [20] in 1961 to measure emotional, cognitive, somatic, and motivational components. The scale is comprised of 21 items that assess five categories: emotions (2 items), cognitions (11 items), behaviors (2 items), somatic symptoms (5 items), and interpersonal symptoms (1 item). This comprehensive approach allows for a thorough assessment of the many dimensions of depression. Scores ranging from 0 to 63 were obtained by assigning a score of 0, 1, 2, and 3 to each question. After completing the 21-item of BDI, scores are assigned to four categories based on the results: none/minimal depression (0–9), mild depression (10–18), moderate depression (19–29), and severe depression (30–63) [20]. The validity and reliability of the scale for use in Turkish society were tested by Tegin [21], ensuring that the scale can be effectively used to assess depression in this population.

The BAI is a self-assessment scale developed by Beck et al. [22] and is used to determine the frequency of anxiety symptoms experienced by individuals. It consists of 21 items, a Likert-type scale, and scored between 0–3. The validity and reliability of the BAI for use in Turkey were evaluated by Ulusoy et al. [23], confirming the effectiveness of the scale for assessing depression in this population.

The YFAS, which was developed by Gearhardt et al. [24] and based on the DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision) substance addiction diagnostic criteria [24] has been validated for use in Turkey through testing conducted by Bayraktar et al. [25]. This comprehensive assessment tool provides valuable insights into food addiction and its impact on individuals.

The scale consists of 27 questions. For food addiction diagnosis, at least 3 of the 7 diagnostic criteria must be met in addition to clinical significance. Clinical significance is defined as the individual’s describing the negative consequences of eating and not being successful enough in controlling the eating behavior despite the negative consequences [25].

BRIAN was developed by Giglio et al. [26] and comprises 21 items that provide a 4-point Likert-type assessment of sleep, activities, social and eating habits, and dominant rhythm pattern (chronotype). This assessment tool has been found to be particularly useful in determining the dominance of “morning” and “night-time” and identifying the disturbance of biological rhythms [27]. The BRIAN has been validated and shown to be reliable for use in Turkey through testing conducted by Aydemir et al. [28]. Its comprehensive assessment of various dimensions of biological rhythms can provide valuable insights into neuropsychiatric disorders. High scores imply greater disturbances in biological rhythms.

BMI was classified according to the proposed criteria of the WHO where BMI of the following values: <18.5 kg/m², 18.5–24.9 kg/m², 25–29.9 kg/m², and ≥30 kg/m² are categorized as underweight, normal weight, overweight, and obese, respectively [29].

The Jamovi (version 2.2; https://www.jamovi.org) computer software package was used to analyze the data. It was determined whether the variables were normally distributed by using Kolmogorov– Smirnov or Shapiro–Wilk’s tests. Descriptive statistics were shown as mean and standard deviation for normally distributed variables. To compare data from different groups, t-tests were used for normally distributed data and Mann–Whitney U tests for non-normally distributed data. To examine the correlation between parameters, Pearson correlation analysis was performed. This study defined statistical significance as a type I error of 5% (p-value 0.05).

According to studies, there is a correlation between food addiction and depression in individuals who are obese. Such individuals have a tendency to consume food as a means of alleviating their depressive symptoms. Additionally, those with food addiction tendencies may seek to increase dopamine levels by consuming palatable and enjoyable foods [30,31]. Recent studies have shown that it is not accurate to associate food addiction solely with depression. In fact, individuals who are obese may display behaviors indicative of food addiction even in the absence of depression [32]. In this case, the idea that food addiction can also be seen in nonobese individuals comes to mind. As a matter of fact, studies have revealed that individuals who are not obese and have no depression also have a food addiction [33,34]. After all, eating is an indispensable physiological need for maintaining life, and we feel happy when we eat because we secrete hormones [35]. When the urge to eat arises due to factors other than physiological hunger, it can potentially lead to pathological conditions and disrupt the natural balance of the body.

In this case, we see that different factors are needed to explain food addiction, and there is still no clear conclusion on this issue [36]. Current researches indicate that food addiction among obese individuals is primarily associated with an increase in body weight and BMI [37,38]. In support of these studies, we found that food addiction increases in proportion to body weight in obese individuals. Furthermore, our research has revealed that the nonobese group does not exhibit a significant correlation between body weight and food addiction. This finding is significant as it highlights the impact of body weight gain on the development of food addiction.

The relationship between obesity and biological rhythm disturbances has been widely studied. Recent studies have shown that biological rhythm disorders are a factor in obesity, as they can affect adipose tissue metabolism, sleep-wake cycles, timing of food intake, and hormonal secretion. Research on this subject continues to grow, indicating the importance of considering the role of biological rhythms in the development of obesity and related disorders [12]. Studies also have shown that CLOCK gene polymorphism associated with biological rhythm increases the risk of obesity and metabolic syndrome [39]. A study involving more than 1,000 patients determined that obese individuals have the shortest daily sleep duration, affecting their biological rhythm [40]. Moreover, it has been demonstrated that in obese individuals, leptin secretion tends to increase during the nighttime hours, along with elevated levels of growth hormone and free fatty acids [41].

In our study, unlike the literature, we found that the disturbance of chronotype decreased with the increase in BMI in obese individuals. Our findings indicate a requirement for further detailed research into the relationship between morning and evening chronotypes and obesity. It is not adequate to solely attribute the relationship between chronotype disorders and obesity.

In this study, we determined that food addiction increased with a disturbance in biological rhythm. In support of our finding, Kandeger et al. [42] showed that biological rhythm irregularities are associated with insomnia and impulsivity in obese individuals, which in turn increase food addiction. Another study showed that food addiction is more prominent in the evening chronotype [38]. Also, the results from studies showing that disruption in sleep rhythm causes increases in the desire to eat support the relationship between the desire to eat and the biological rhythm [43]. Yilbas et al. [44] showed that food addiction is more common in evening chronotype individuals with attention deficit hyperactivity symptoms independent of obesity in university students. Additionally, studies have found that individuals with obesity tend to have disrupted biological rhythms, including changes in sleep-wake cycles and alterations in the timing of food intake. These disturbances in biological rhythms can further exacerbate food addiction behaviors, leading to a vicious cycle of overeating and weight gain. Therefore, it is crucial to consider the role of biological rhythms in the development of food addiction in obesity, as interventions targeting circadian misalignment and other biological rhythm disruptions may be effective in preventing and treating addictive-like eating behaviors in individuals with obesity.

The outcomes of these studies, as well as our own findings, are significant in that they demonstrate the associated impact of disturbances in biological rhythms on an individual’s appetite. It is plausible to consider that maintaining regularity in biological rhythms and living in harmony with the natural balance can have a positive effect on the physiological regulation of appetite. By regulating one’s desire to eat, it is conceivable that individuals may be better protected from the development of obesity.

We have obtained several results from this study. Firstly, the presence of depression in obese individuals was not correlated with body weight, BMI, or %F. Secondly, depression was correlated with disruptions in biological rhythm in obese individuals. Thirdly, food addiction was associated with depression, anxiety, and biological rhythm disruptions in obese individuals. In the nonobese group, food addiction was only associated with depression. Fourthly, food addiction was not associated with adipose tissue parameters in obese individuals, and it is seen that there is limited information in the literature to explain this relationship. Adipose tissue parameters and obesity are closely interrelated. Adipose tissue is a connective tissue that plays a significant role in energy metabolism, storage, and release. Obesity is characterized by an excessive accumulation of adipose tissue, leading to an increase in body weight and BMI. Several adipose tissue parameters are associated with obesity, including adipose tissue thickness, volume, distribution, and adipocyte size. In obese individuals, the adipose tissue parameters are significantly altered, leading to metabolic dysfunction, insulin resistance, and chronic inflammation. Additionally, obesity-related adipose tissue dysfunction is linked to the development of several metabolic disorders. Therefore, understanding the adipose tissue parameters and their relationship to obesity is crucial in developing effective preventive and therapeutic interventions for obesity-related disorders. This result also suggests that there is a need for detailed studies on the relationship between adipose tissue metabolism and food addiction. As a result, if the person is both obese and has been diagnosed with food addiction with the YFAS test, obesity may have emerged as a continuation of depression, anxiety, and biological rhythm disruptions.

In conclusion, our study highlights the importance of considering depression, anxiety, and biological rhythm disruptions in the development of food addiction and obesity. The results suggest that disruptions in biological rhythms may play a significant role in the development of food addiction in obese individuals. Moreover, our findings indicate that there is a need for more detailed studies to understand the relationship between adipose tissue parameters, food addiction, and obesity. Effective preventive and therapeutic interventions for obesity-related disorders could be developed by understanding the relationship between adipose tissue parameters and obesity. Overall, the study emphasizes the complexity of the relationship between food addiction, biological rhythms, and adipose tissue metabolism, indicating the need for further research in this area.