An analysis of National Health and Nutrition Examination Survey (NHANES) data revealed that each additional fast-food meal per week was associated with a 4% higher likelihood of depression. This association was largely independent of obesity, although obesity did mediate the link to some extent, particularly in individuals with severe obesity. The study was published in the Journal of Affective Disorders.
Fast food refers to meals that are prepared and served quickly. It is sold in restaurants, drive-throughs, or takeaways, emphasizing convenience for busy consumers. Common examples of fast food include burgers, fries, pizza, fried chicken, and sandwiches. While fast food is often less expensive than dining at full-service restaurants, it is typically high in calories, unhealthy fats, sugar, and salt—all of which can contribute to excessive calorie intake and weight gain.
Fast food has become a staple in many cultures, driven by urbanization, fast-paced lifestyles, affordability, and appealing taste. Critics of fast food highlight its potential role in contributing to obesity and health issues, while proponents emphasize its accessibility and affordability. Numerous studies have linked fast food-based diets to an increased risk of obesity. Research has also found that children living near fast-food restaurants tend to consume fewer servings of fruits and vegetables and are more likely to be overweight.
Study author Arman Shafiee and his colleagues sought to further explore the relationship between fast food, obesity, and depression. They were particularly interested in whether obesity might mediate the link between fast food consumption and depression. According to this hypothesis, increased fast food consumption could lead to obesity, which, in turn, could contribute to depression.
The researchers analyzed data from NHANES, a program conducted by the National Center for Health Statistics (NCHS), part of the Centers for Disease Control and Prevention (CDC) in the United States. NHANES is a nationally representative survey designed to assess the health and nutritional status of adults and children in the United States.
Data for this analysis came from 17,460 NHANES participants, with an average age of 48 years. Among these, 15,960 were women. Depression data were obtained using the 9-item Patient Health Questionnaire, while dietary information was collected by asking participants how many meals they consumed from fast-food or pizza establishments in a typical week.
The results showed that 11% of participating women and 7% of men exhibited clinical levels of depression symptoms. Individuals with higher levels of education were less likely to experience depression. Participants consuming more than two fast-food meals per week had 24% higher odds of depression compared to those consuming fewer than two fast-food meals per week.
Further analysis revealed that the relationship between fast food consumption and depression was largely independent of obesity, with obesity contributing negligibly to the overall link. However, the relationship differed among individuals with moderate and severe obesity. Statistical analyses of these subgroups supported the hypothesis that obesity might mediate the link between fast food consumption and depression. Specifically, fast food consumption may exacerbate obesity in these individuals, which, in turn, could worsen their depression symptoms.
“The association between fast food consumption and depression is clear, and the relatively low mediating effect of obesity underscores the need for a comprehensive approach to promoting mental well-being. Public health strategies should prioritize not only weight management but also healthier dietary choices, recognizing that what we eat plays a crucial role in our mental health,” the study authors concluded.
The study contributes to the scientific understanding of the links between nutrition and mental health. However, it should be noted that for the overall sample, the mediating effect of obesity on the link between fast food consumption and depression was negligible. Additionally, the study’s design does not allow for causal conclusions to be drawn from the findings.
The paper, “Contribution of obesity in the association between fast-food consumption and depression: A mediation analysis,” was authored by Arman Shafiee, Sepehr Aghajanian, Ehsan Heidari, Mohammad Abbasi, Kyana Jafarabady, Sania Baradaran, and Mahmood Bakhtiyari.
