According to research, eating healthily has been shown to improve physical fitness. This study offers some of the most robust evidence linking healthier diets with increased fitness. Individuals consuming healthier diets saw improvements that were equivalent to taking an additional 4,000 steps per day – further evidence supporting their connection.
Cardiorespiratory fitness refers to an individual’s ability to provide and use oxygen during physical activity, and is comprised of multiple organ systems such as muscles, blood vessels, lungs and heart health. Cardiorespiratory fitness is one of the best indicators of future health and longevity.
Exercise may enhance cardiorespiratory fitness, yet individuals exercising an equal amount can have different fitness outcomes, suggesting other contributing factors may also play a part. Diet is associated with various health benefits; however it’s unclear whether its influence is also having an effect on fitness levels.
This study investigated whether diet was related to physical fitness among 2,380 individuals averaging 54 years old from the Framingham Heart Study.
For measuring Peak Volumac Index (VO2), a cardiopulmonary exercise test was carried out on a cycle ergometer with maximum effort, representing the gold standard fitness assessment method, to demonstrate how much oxygen was utilized during maximum intensity physical exercise.
The Harvard Food Frequency Questionnaire was also used to assess consumption of 126 dietetic items over the last year, from never or less than once every month up to six or more daily servings.
Information was used to rate the quality of diet using both the Mediterranean-style Diet Score of 0-25 and Alternative Healthy Consuming Index from 0-110, both linked to heart health. Higher scores indicated a healthier diet that prioritized fruits, vegetables, whole grains, legumes, nuts, fish and healthy fats while restricting alcohol and red meat consumption.
After controlling for other variables that could influence the relationship, including gender, age, BMI, daily energy consumption levels, cholesterol levels, smoking status, diabetes risk status and blood pressure; we assessed how diet quality impacts fitness.
Average Alternative Healthy Consuming Index and Mediterranean-style Diet Scores were 66.7 and 12.4, respectively. Comparing to this baseline score, increasing by 13 points on either index was linked with 5.2% higher peak VO2.
Middle-aged individuals were found to benefit from adopting healthy dietary patterns even when taking into account activity levels and habitual physical activity levels. The correlation was equally noticeable between men and women and younger individuals (54 years or under).
Researchers conducted additional analyses in order to gain more insight into the mechanism that underlies the relationship between fitness and diet, with further examination focusing on quality diet, fitness, and metabolites (produced during digestion but released into blood streams during exercise).
1.154 individuals provided blood samples to measure 201 metabolites; 24 of these metabolites were linked with either favorable or poor diet and fitness despite previous analyses taking similar factors into account.
Metabolite data indicate that healthy eating habits are linked with improved metabolic health, which could explain why such practices lead to improved fitness.
As this was an observational study, no direct conclusions can be drawn as to whether eating healthily leads to increased fitness; alternatively, fit people might opt for healthier eating patterns as part of their regimen.
