It’s tempting to think you can regularly indulge in a plate of fettuccine Alfredo or a huge slice of cheesecake and erase the negative health effects with an intense workout. But that’s just not the case, a new study has found.
Exercise does not fully compensate for a poor diet when it comes to living longer, researchers reported this month in the British Journal of Sports Medicine. Separate research has previously found exercise likely doesn’t help people lose weight.
The new study dismissed “sensationalized” headlines and “misleading” ads for exercise regimens that “lure consumers into the idea of ‘working out to eat whatever they want.’”
Dietary quality still matters in those who are very physically active, said Melody Ding, the lead author and an associate professor in the department of medicine and health at the University of Sydney in Australia.
“Participants with the lowest mortality risk were the ones with high levels of physical activity and high-quality diet consistently across all three outcomes: deaths from all causes, deaths from cardiovascular disease and deaths from cancer,” Ding told TODAY.
“Exercise still protects against mortality risk even if someone has a bad diet, it is just that it is much better to have both exercise and a good diet.”
The impact of diet and exercise
As a very active person herself, Ding set out to do the study because she was curious about the possibility of “outrunning a bad diet” when it came to longevity. “Sometimes when I have craving for potato wedges or cheesecakes, I do wonder whether I have more ‘immunity’ against a bad diet,” she said.
To get the answer, she and her colleagues turned to a large database of British adults who reported their diet and exercise habits. The study sample included more than 346,000 participants in all.
They were considered to have a high-quality diet if they ate at least 4.5 cups a day of fruits and vegetables, and two servings a week of fish, while limiting their servings of processed meat and red meat to twice per week or less, and five times per week or less, respectively.
It was challenging to record all aspects of people’s diet in such a big a sample so the data didn’t include how often the participants consumed sugary drinks, fast food and other discretionary choices, Ding noted. “It is a real pity… I hope that we can address that in the future,” she added.
When it came to exercise, the participants were grouped by how many minutes per week they engaged in vigorous-intensity physical activity — the type that would leave them out of breath, such as running, aerobic dancing and heavy gardening, Ding said. Previous research suggests this type of movement may offer additional health benefits compared to moderate activity alone.
'It is not just a matter of energy balance'
After the participants were followed for an average of 11 years, the researchers examined how many died and their cause of death.
It turned out the people with the lowest risk of dying prematurely almost always had the highest-quality diet and engaged in the highest or second-highest amount of physical activity, which meant at least 75 minutes of vigorous-intensity physical activity per week.
But high levels of physical activity did not fully counteract the detrimental effects of a poor diet on mortality risk, the study found.
“I had some wishful thinking during the conceptualization of the project, but the results were not a surprise to me. I anticipated that diet still matters — even for the most active,” Ding said.
“We need to both move our body and eat well. Diet and physical activity both affect health through many mechanisms; it is not just a matter of energy balance. We need to think beyond ‘whether I can burn off that cake through exercise.’ Eat and exercise for overall health.”
Focus on healthy behaviors most of the time
Diet is the leading risk factor for seven of the 10 leading causes of death and disability, said Maya Vadiveloo, an assistant professor in the department of nutrition and food sciences at the University of Rhode Island. She wasn’t surprised by the study findings.
On the flip side, someone eating a very nutritious diet, but sitting on the couch all day isn’t doing their body any favors either because both diet and exercise matter for long-term health, she noted.
“Multiple elements of our lifestyle are important for health: We want to be eating healthy diets and we want to move our bodies," Vadiveloo, who was not involved in the new study, told TODAY.
Still, experts know most people aren’t saints leading perfectly healthy lives. If a person sometimes wants to have dessert, but is choosing fresh fruits, vegetables, whole grains, low-fat dairy, plant sources of protein, fish and heart-healthy oils most of the time, “I wouldn’t worry about that when the overall context is healthy,” Vadiveloo said.
For potato chip or cookie cravings, she recommended limiting the portion size and how often you indulge, but not forbidding those foods altogether because that becomes very hard to stick to.
To stay healthy, pay attention to what makes your body feel good, both from a diet and exercise perspective, Vadiveloo advised. If you’re sedentary because you hate running, try walking, dancing or swimming. If you’re eating too much junk food, add a few healthier options that you still find enjoyable, like nuts or sweet potatoes.