The idea that running the treadmill “neutralizes” the harm of having pizza and cake for lunch sounds comforting. But the new study shows that high levels of physical exercise do not counteract the detrimental effects of a poor diet on mortality.
The study led by the University of Sydney researchers, found that participants with both high levels of physical activity and a high-quality diet had the lowest risk of death.
Researchers examined the independent and joint effects of diet and physical activity with all-cause, cardiovascular disease, and cancer mortality.
They found out that participants with high levels of physical activity and a high-quality diet had mortality risk reduced by 17 percent from all causes, 19 percent from cardiovascular diseases, and 27 percent from selected cancers, compared with those with the worst diet who were physically inactive.
“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,” said lead author, associate professor Melody Ding at the University of Sydney.
Scientists have previously linked poor diet to various diseases, including cancers.
Tufts University researchers estimated that diet-related factors might account for 80,110 of the new invasive cancer cases reported in 2015 or 5.2 percent of that year's total among U.S. adults. More than 52,000 cases were colorectal cancer.
The Centers for Disease Control and Prevention (CDC) data shows that fewer than 1 in 10 adolescents and adults in the U.S. eat enough fruits or vegetables. At the same time, 9 in 10 Americans consume too much sodium, most of which comes from packaged, processed, store-bought, and restaurant food.
What is a high-quality diet?
The World Health Organization calls unhealthy diet and lack of physical activity leading global risks to health.
The WHO recommends eating at least 400 g., or five portions, of fruit and vegetables per day to ensure an adequate daily intake of dietary fiber. It can be done by always including vegetables in meals or eating fresh fruit and raw vegetables as snacks.
A total fat intake can be reduced by steaming or boiling instead of frying when cooking and replacing butter with oils rich in polyunsaturated fats, such as soybean or sunflower oil.
Reducing salt intake to the recommended level of less than 5 g per day is crucial. In addition, adults should have no more than 30 g of free sugars a day.