Turns out, intense exercise can’t counteract the detrimental effects of a poor diet.

This is according to a new study led by The University of Sydney, which found that people with high levels of physical activity and a high-quality diet had the lowest risk of death, showing that exercise could not outrun a poor diet.

With the findings published recently in the British Journal of Sports Medicine, the researchers used a large population (360,600) of British adults from the UK Biobank, a large-scale biomedical cohort study containing in-depth biological, behavioral, and health information from participants. The researchers examined the independent and joint effects of diet and physical activity on all-cause, cardiovascular disease and cancer mortality.

The study revealed that participants who combined a high-quality diet with high levels of physical activity lowered their mortality risk by 15% from all causes, 19% from cardiovascular disease, and 27% from certain cancers. This is compared to those who were not only physically inactive but had the worst diet.

"Both regular physical activity and a healthy diet play an important role in promoting health and longevity,” said lead author and associate professor Melody Ding from the Charles Perkins Center and the Faculty of Medicine and Health at the University of Sydney.

“Some people may think they could offset the impacts of a poor diet with high levels of exercise or offset the impacts of low physical activity with a high-quality diet, but the data shows that, unfortunately, this is not the case,” Ding said.

Co-author Joe Van Buskirk, from the School of Public Health, Faculty of Medicine and Health, also weighed in on the issue, saying that anyone who wants to reduce the risk of death from all causes should adhere to “both a quality diet and sufficient physical activity.”

Previously, a small number of studies found that high-intensity exercise may be able to counteract the detrimental effects of over-eating. However, the long-term effects on how diet and physical activity interact remained less explored.

The new study confirmed the importance of physical activity and diet in improving quality of life.