Unhealthy diets may accelerate biological aging—Even in your 20s, study finds

A recent study published in the Journal of Clinical Nutrition suggests that unhealthy dietary patterns—high in fast food, processed meats, and sugary beverages—may accelerate biological aging, even in young adults. Researchers analyzed the diets of 826 individuals aged 21–25, using advanced epigenetic clocks to assess biological aging.

Biological vs. Chronological Age: Understanding the Difference

Chronological age simply counts the years since birth, but biological age reflects how well our bodies are aging at a cellular level. Scientists use DNA methylation-based epigenetic clocks to measure biological age and aging acceleration.

The two primary epigenetic clocks used in this study were:

• GrimAge: Estimates the difference between biological and chronological age to predict life expectancy.
  DunedinPACE: Measures the pace of aging by calculating how many biological years pass per chronological year.

These tools have been linked to long-term health outcomes, making them valuable for aging research.

How Diet Influences Aging

The study found a clear relationship between dietary patterns and biological aging:

• Diets rich in fruits and vegetables and low in processed meats, fast food, and soda were linked to slower biological aging.
• Conversely, diets low in fresh produce and high in processed foods and sugary drinks were associated with accelerated aging.

While this aligns with previous findings in older adults, the fact that these effects were already visible in young adults is noteworthy.

What the Experts Say

Dr. Suvi Ravi, a postdoctoral researcher at the University of Jyväskylä in Finland and one of the study’s authors, stated that these findings were expected based on prior research.

“I was not surprised,” said Dr. Ravi. “The results are consistent with studies in middle-aged and older populations, as well as the few studies conducted on younger individuals.”

Other experts echoed similar sentiments. Dr. Benjamin Reiner, a research assistant professor at the University of Pennsylvania, emphasized that dietary choices can modify epigenetic markers and have lasting health effects.

Other Lifestyle Factors Matter Too

The researchers accounted for additional variables such as body mass index (BMI), physical activity levels, smoking, and alcohol intake. When these factors were considered, the link between diet and aging became less pronounced, suggesting that exercise and other healthy habits may offset some negative effects of a poor diet.

Limitations and Future Research

While epigenetic clocks are a groundbreaking tool, they have limitations. One concern is that they are often developed based on specific populations, which may affect accuracy when applied to different ethnic groups. Future studies should explore population-specific epigenetic models.

Dr. Ravi and her research team are now investigating how genetic risk factors, particularly those linked to obesity, interact with diet and other environmental influences on aging.

Can a Healthier Diet Reverse Biological Aging?

The good news? Experts believe dietary improvements may help slow or even reverse aspects of biological aging.

“There is evidence that diet modification can slow down epigenetic aging, at least in older individuals,” Dr. Ravi noted.

As obesity-related health issues rise and weight-loss medications like GLP-1 receptor agonists gain popularity, understanding how diet and lifestyle affect epigenetic aging will be critical for developing future health interventions.

The Bottom Line

This research reinforces the importance of a nutrient-rich diet from an early age. Incorporating more fruits, vegetables, and whole foods while reducing processed foods, sugary drinks, and fast food may be key to maintaining youthful biology and preventing age-related diseases.

With the science of epigenetics still evolving, new discoveries will likely provide even greater insight into the intricate relationship between diet, DNA, and aging.