Junk food can cause depression, loss of resilience and adaptability - study

The widespread consumption of ultra-processed food (UPF) has long been linked with a variety of diseases, including obesity, heart disease, stroke, hypertension, and type-2 diabetes. A new study has now linked UPF to depression and other mental illnesses – especially in wealthy countries such as the US and the UK, where the majority of calories consumed today come from UPF.

The 21-page report by researchers at the Sapien Labs, a nonprofit organization based in Washington, DC, on “a mission to understand and enable the human mind,” showed an improvement of depression symptoms even after just three weeks of dietary change in those who regularly consume a diet of UPF.

To examine how far-reaching the effects of UPF on mental health are, the team looked at the self-reported frequency of UPF consumption and its relationship to the full breadth of mental-health symptoms, plus an aggregate of mental well-being, in a global sample of almost 300,000 people.

The study, entitled “Consumption of ultra-processed food and mental well-being outcomes,” found that mental well-being decreases sharply with more frequent UPF consumption. The higher frequency of UPF consumption impacts all dimensions of mental function, including adaptability and resilience to cognition, the researchers warned. Depression symptoms and problems with cognitive and emotional control dominated with a higher frequency of UPF consumption.

Those who consume UPF several times a day are three times more likely to have serious mental-health struggles compared with those who rarely or never do. While younger adults consume UPF more frequently, such eating has a similar impact on all age groups, according to the study.

Young adults aged 18 to 24 were found to have a dramatically worsened mental well-being, and they consume UPFs substantially more frequently compared with older age groups.

The decline in mental well-being with increased frequency of UPF consumption, the authors said, cannot be attributed to indirect effects of exercise frequency or income.

The key symptoms that worsened with increasing UPF consumption were appetite regulation, feelings of sadness, distress, and hopelessness, as well as challenges with controlling thoughts and emotions, such as unwanted thoughts and anger.

Trends from across the globe

Among 26 countries compared, respondents in the Philippines, the US, and the UK reported the highest consumption of UPF, while those in Egypt, Morocco, and Venezuela reported the lowest. Israel was not included in the study.

This study uses global data from 292,786 respondents aged 18 to 75-plus obtained between January and August 2023 through the Global Mind Project. Data included an assessment that spanned 47 elements covering a wide range of symptoms and mental capabilities, and it provides aggregate scores of mental well-being and its dimensions.

The changes with increased UPF consumption are distinct from the negative effects of smartphones that were previously reported and may be additive in nature, the authors wrote.

Altogether, the growing UPF consumption appears to progressively diminish the mental capabilities of the population.

Furthermore, it is possible that UPFs are responsible for up to a third of the mental-health burden in countries where UPF consumption is over half of calories consumed, such as the US and the UK, they wrote.