Exercise Helps Offset Mental Effects of Junk Food: Study

New Delhi: People who consume large amounts of junk food may be able to reduce its negative effects on mental health through regular cardio exercise such as running, according to a new study conducted by researchers at the University College Cork, Ireland.

The study identified specific metabolic pathways through which physical activity counteracts the adverse behavioural impacts of a Western-style diet high in fat and sugar.

Published in the journal Brain Medicine, the research revealed that voluntary running exercise helped reverse depression-like behaviours in animals that were fed unhealthy diets.

Led by Professor Yvonne Nolan, the study exposed adult male rats to either standard chow or a rotating “cafeteria diet” rich in fats and sugars for over seven weeks. Half of the rats in each group had access to running wheels.

The results showed that exercise produced antidepressant-like effects even among those consuming a poor diet, indicating that physical activity can benefit mental health despite poor eating habits.

The researchers found that the high-fat, high-sugar diet significantly altered the gut metabolome, affecting 100 out of 175 measured metabolites. Exercise influenced only a subset of these changes but partially restored key mood-related metabolites anserine, indole-3-carboxylate, and deoxyinosine, which had decreased due to the unhealthy diet.

While the junk food diet did not severely impair memory or learning, exercise led to slight improvements in spatial navigation and reduced anxiety-like behaviours, regardless of diet quality.

The findings highlight that regular exercise can improve mood and mental well-being even with poor nutrition, though achieving full brain benefits may require combining physical activity with healthy eating.

The researchers suggest that such insights could guide lifestyle interventions promoting both mental and physical health in an era dominated by ultra-processed food consumption.