Eating ultra-processed foods (UPF) like burgers, pizzas and diet coke is associated with an increased risk of depression, according to a study.

The findings, published in the JAMA Network Open Journal, suggest that eating energy-dense, palatable, and ready-to-eat items, including grain foods, sweet and savoury snacks, ready-made meals, and beverages with artificial sweeteners, processed meat, dairy products, fats, and sauces, can raise the risk of depression.

"Although the mechanism associating UPF to depression is unknown, recent experimental data suggests that artificial sweeteners elicit purinergic transmission in the brain, which may be involved in the etiopathogenesis of depression," said researchers from Harvard University in the US.

Prior studies have been hampered by short-term dietary data and a limited ability to account for potential confounders. Additionally, no study has identified which UPF foods and/or ingredients that may be associated with the risk of depression or how the timing of UPF consumption may be associated.

To understand, the team investigated the prospective association between UPF and its components with incident depression. They included 31,712 females, aged 42 to 62 years, between 2003 and 2017.

The results indicated a staggering 49 per cent high risk of developing depression in women who consumed nine or more portions of ultra-processed foods daily, compared to those who ingested fewer than four portions.

Women who decreased their ultra-processed food consumption by at least three servings daily showcased a diminished risk of depression compared to those maintaining a consistent intake, the study showed.

Increased consumption of ultra-processed foods also leads to obesity and keeps blood sugar levels consistently high, increasing the risk of developing Type 2 diabetes. This in turn can also increase the risk of heart disease, stroke and cancer.