New research suggests that eating a healthy diet emphasizing more foods like fruit, vegetables, and whole grains can be as good as taking an additional 4,000 steps a day – and particularly for middle-aged adults.
A person’s cardiorespiratory fitness refers to the body’s ability to provide and use oxygen for exercise, involving the heart, lungs, blood vessels and muscles. Research has shown that it’s one of the most powerful predictors of longevity and health, and getting regular physical activity can improve one’s endurance.
But among people who exercise the same amount, there are still differences in fitness – suggesting there are additional factors that contribute. Eating a nutritious diet is linked to countless health benefits, but according to the study team, it’s been unclear whether it’s also related to fitness.
"This study provides some of the strongest and most rigorous data thus far to support the connection that better diets may lead to higher fitness," study author Dr. Michael Mi of Beth Israel Deaconess Medical Center in Boston said in a statement. "The improvement in fitness we observed in participants with better diets was similar to the effect of taking 4,000 more steps each day."
The findings of the study, published on April 28 in the European Journal of Preventive Cardiology, suggests that certain dietary habits can lead to better metabolic health and lead to improved fitness and ability to exercise.
The study included 2,380 Americans, with an average age of 54 and more than half (54%) being women. The team measured their oxygen levels during exercise on a cycle ergometer. The participants also completed a Harvard food frequency questionnaire to assess their consumption of 126 food items over the past year.
Their responses, ranging from never or less than once per month to six or more servings per day, were used to rate diet quality using the Alternative Healthy Eating Index and Mediterranean-style Diet Score, which are both linked to heart health.
A higher score indicated a better quality diet, emphasizing vegetables, fruits, whole grains, nuts, legumes, fish and healthy fats and limiting red meat and alcohol.
The team also controlled for other factors, including age, sex, total daily energy intake, body mass index, smoking status, cholesterol levels, blood pressure, diabetes and routine physical activity level.
"In middle-aged adults, healthy dietary patterns were strongly and favourably associated with fitness even after taking habitual activity levels into account," Mi said. "The relationship was similar in women and men, and more pronounced in those under 54 years of age compared to older adults."
However, the team cautioned how the study was observational, and they could not conclude that eating well causes better fitness, "or exclude the possibility of a reverse relationship, i.e. that fit individuals choose to eat healthily."
Regardless, eating a Mediterranean-style diet – one with plenty of fruits, vegetables, bread and other grains, potatoes, beans, nuts and seeds – was recommended for its role in preventing heart disease and stroke and reducing risk factors for other health issues.
"There are already many compelling health reasons to consume a high-quality diet, and we provide yet another one with its association with fitness," Mi said of the findings. "A Mediterranean-style diet with fresh, whole foods and minimal processed foods, red meat and alcohol is a great place to start."
This story was reported from Cincinnati.