The Obesity Accelerator: Does Being Overweight Speed Up Aging?

For nearly a century, the secret to a longer life was a stark one: calorie restriction. Studies on everything from yeast to mice have shown that significantly reducing calorie intake can extend lifespan. This led to a powerful, if punishing, idea that experiencing a bit of hunger was the price for longevity.

But what if we’ve been looking at the equation the wrong way? A compelling new commentary in JAMA Network Open by Dr. Antonello Lorenzini suggests we reframe the question. Is it that calorie restriction slows aging, or is it that obesity actively accelerates it? New evidence suggests the latter may be the more crucial insight for our modern world.

Your Biological Age vs. Your Birthday

To answer this question, we need a way to measure aging that goes beyond counting years. Scientists now use powerful tools called epigenetic clocks to determine a person’s “biological age.” Think of it as measuring the real-time “wear and tear” on your DNA. These clocks analyze chemical tags on your genes (DNA methylation) to estimate your cellular age, which can be older or younger than your chronological age.

A groundbreaking recent study put these clocks to the test. Researchers analyzed data from the Santiago Longitudinal Study, following participants from birth into their late 20s. The results were stunning.

Young adults who had a high Body Mass Index (BMI) since childhood or adolescence were found to be biologically 2.2 to 4.7 years older than their actual age. The effect was so clear and consistent that, despite some variability, the data “speak for themselves.” A lifetime of carrying excess weight had left a measurable, aging scar on their DNA.

Rethinking the “Magic” of Calorie Restriction

This finding prompts us to reconsider why calorie restriction is effective in laboratory animals. As Dr. Lorenzini points out, lab mice and monkeys are often fed “ad libitum” an all-you-can-eat buffet. This conventional approach frequently leads to unintentional weight gain. Calorie restriction, in this context, may not be a magic anti-aging intervention so much as an anti-obesity one. Its main benefit could simply be preventing the accelerated aging caused by being overweight.

This idea is further supported by the fact that the biological “hallmarks of aging” the fundamental processes that cause our bodies to decline, show a clear and undeniable overlap with the biological processes that define obesity. From inflammation to metabolic dysfunction, obesity appears to be a state that mimics and hastens the aging process.

The Real Recipe for a Long, Healthy Life

This shift in perspective is incredibly empowering. It suggests that the path to longevity isn’t about deprivation or constant hunger. As Dr. Lorenzini concludes, the goal is not to starve, but to prevent the state of accelerated aging that accompanies obesity.

The recipe for a long and healthy life, therefore, becomes much more achievable:

• Modify your diet: Focus on increasing foods that prevent obesity (whole fruits, vegetables, lean proteins) while reducing those that promote it (highly processed foods, sugary drinks).
• Engage in appropriate physical activity: Movement is essential for maintaining a healthy metabolic state.
• Manage stress: Both mental and physical stress can contribute to weight gain and influence biological aging.

Ultimately, this research provides another powerful reason to address the global obesity epidemic. Being overweight is not just a risk factor for future diseases; it is a condition that can accelerate the aging process today. By focusing on maintaining a healthy weight, we are not just adding years to our lives, but adding life to our years.

Lorenzini A. Calorie Restriction, Obesity, and the Aging Process. JAMA Netw Open. 2025;8(7):e2522387. doi:10.1001/jamanetworkopen.2025.22387

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