Fitness: Exercise can’t outrun a bad diet

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We’ve all justified diving deep into a big bag of chips or a pint of ice cream after a workout by telling ourselves we’ve earned it. But did we really do it?

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The idea that spending a few extra minutes on the treadmill protects you from the consequences of dietary vices is tempting. However, there is little evidence that an unhealthy diet can be mitigated with regular exercise, a theory recently tested by a group of researchers from Australia, the US, Italy and Norway. Using a large sample of British adults, the multinational team reviewed the impact of exercise and diet, independently and jointly, on mortality from all causes, cardiovascular diseases and various types of cancer.

Armed with the self-reported health history and diet and exercise habits of 346,627 study subjects aged 40 to 69, the researchers compared the data to local death records over the course of a decade. The idea was to link cause of death to baseline health records collected 10 or 11 years earlier and measure the impact of diet, exercise, or a combination of the two on mortality.

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The researchers were motivated by the dearth of studies examining the long-term health outcomes of diet and exercise, but they were also eager to add another layer of complexity, looking at whether vigorous exercise offered some additional protection against the risk of premature death compared with more moderate exercise intensity.

“We hypothesize that physical activity and diet quality are independently associated with lower mortality risk, and that high levels of physical activity, either moderate-to-vigorous total physical activity or vigorous-to-vigorous physical activity , they cannot compensate for the detrimental effects of a poor-quality diet. ”, the researchers said.

The study subjects appeared to be a reflection of Western society: 40.8% did not exercise vigorously during the week, 26.5% did less than 75 minutes of high-intensity training per week, and the rest spent more 75 minutes a week of vigorous exercise. For diet, 22 percent rated poor, 53.4 percent rated average, and 24.5 percent rated the healthiest diet category.

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The good news is that, when viewed separately, high levels of physical activity (211 to 450 minutes of moderate to vigorous exercise per week) and a high-quality diet have a positive influence on longevity. And for those who can claim to excel at both, congratulations: You have an even lower mortality risk.

But for those hoping that exceeding expectations in one healthy habit might make up for failure in another, the results are eye-opening.

“Overall, there is no evidence of high levels of physical activity, measured as moderate-to-vigorous or vigorous physical activity, fully compensating for low diet quality in any of the analyses; there was also no evidence of a higher diet quality index fully compensating for lack of physical activity,” the researchers said.

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Still, some additional findings turned out to be interesting. Vigorous physical activity provided slightly greater protection against cardiovascular disease than moderate-intensity exercise, but only for those who accumulated 10 to 150 minutes per week of vigorous exercise. Those who logged more than 150 minutes a week did not see the same increase in benefits.

It’s also worth noting that those with the healthiest diets had a 14 percent lower risk of cancer mortality, a benefit that did not extend to those with a low- or medium-quality diet. Before you give up ice cream or chips forever, rest assured that the occasional indulgence won’t have a negative impact on your long-term health and well-being. But what is clear is that a love of exercise cannot mitigate the negative effects of a love of fast food.

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If you want to reduce your risk of chronic disease and premature death, the best thing you can do is pay equal attention to exercise and eating well. If you want an extra boost for your health, it’s a good idea to add some, but not too much, vigorous exercise to your routine. Just keep in mind that there are no shortcuts to being as healthy as possible. Improving your diet and putting in minutes of exercise are worth it, in the short and long term.

“Sensational headlines and misleading advertising of exercise regimens to lure consumers into the idea of ​​’exercising to eat what you want’ have fueled the circulation of the myth that ‘exercise beats a bad diet,'” they said. the researchers. “Our study provided important evidence for health professionals that exercise does not fully compensate for a poor diet and that we should recommend and advocate both an active lifestyle and a healthy diet.”

Words to live by if you’re in the habit of rewarding yourself with a trip to Tim Hortons drive-thru after every hard workout. Better to go straight home for a healthy dose of fruits and vegetables.