A Healthy Diet Is Not Enough, You Need Exercise to Live Longer Too

By Jiri Kaloc

You can’t outrun a bad diet. You can’t out-diet a sedentary lifestyle. A new study shows that we need to think about diet and exercise differently. It’s not just about burning calories. The basics in both arenas are important to get right.

Healthy eating and exercise are both good for us, as most people probably know. But there are still many people who go to the gym to “burn-off” those extra donuts.

“Sensationalised headlines and misleading advertisements for exercise regimens to lure consumers into the idea of working out to eat whatever they want have fuelled circulation of the myth about exercise outrunning a bad diet,” wrote the study’s authors.

To be fair, research does show that doing a lot of exercise can prevent you from gaining weight after overeating in the short-term. The problem is the impact of regular overeating on other aspects of health as well as the fact that maintaining a high volume of exercise is not always possible.

A new study published in the British Journal of Sports Medicine decided to evaluate the independent and interactive effects of both diet and exercise on all-cause, cardiovascular disease, and cancer mortality. The researchers examined data from nearly 350,000 participants. The study participants, median age 57, were healthy at the beginning of the study.

A healthy diet is not enough. © Profimedia, Caia Image

What a healthy diet looked like

The research team analysed each participant’s diet based on self-reported questionnaires. They defined high-quality diets in the following way: at least four and a half cups of fruit and vegetables per day, two or more servings of fish per week, fewer than two servings of processed meats per week and no more than five servings of red meat per week.

“These food groups were selected as markers for overall diet quality because other important dietary components and/or nutrient groups, such as whole grains and dairy, were not measured during baseline assessment,” the authors commented.

Physical activity levels were also evaluated based on a questionnaire. Participants were asked how many minutes they spent walking, engaging in moderate physical activity (steady-state cycling, light weights), and vigorous physical activity that lasted more than 10 minutes at a time.

Active people who eat well have the lowest risk

The researchers found that participants with the highest activity levels who also ate the highest-quality diet reduced their risk of all-cause mortality by 17%, reduced their mortality risk of cardiovascular disease by 19% and cancers by 27% when compared to those with the lowest quality diet and the lowest amount of exercise. Interestingly, the highest-quality diet by itself without exercise had no effect on all-cause mortality risk or cardiovascular mortality risk.

The lead author of the study, Dr. Ding, summarised the results: “Regardless of your diet, physical activity is important. And whatever your physical activity is, diet is important.”

Focusing only on one thing is not enough

The study showed that almost any amount of exercise is protective. It also showed that better eating habits reduce the risk of mortality too. But trying to optimise only one of these is not going to bring as much benefit as when you address both.

Advice for exercisers: be intentional about eating. Don’t think of food only as calories to burn during exercise. Make small improvement in what you eat and stick with them over the long term. Extreme diets and quick fixes typically do more harm than good, so avoid those.

Advice for dieters: get moving. Don’t rely solely on your diet to protect you. The study shows that even 10 to 75 minutes of exercise per week showed positive effects. Don’t start too fast or too heavy because you could injure yourself or burn out. Find enjoyable sports or ways to move and make them a regular part of your lifestyle.