Cutting calories may slow aging in key body systems

Introduction

This study looked at whether eating fewer calories over two years could slow the aging of different body systems in humans. Aging affects organs at different rates, and the researchers wanted to see if cutting calories could keep some systems younger.

What the study did

The study was a randomized controlled trial, meaning participants were randomly assigned to one of two groups. One group ate about 20% fewer calories than usual, while the other ate normally. The researchers followed 185 adults for up to two years. They measured biological age—a way to estimate how old the body's systems act—for the heart, immune system, kidneys, liver, and metabolism, plus the whole body.

What it found

• Calorie restriction slowed the aging of the metabolic system by about 0.5 to 0.6 years compared to normal eating.
• It slowed cardiovascular aging by about 0.8 to 1.0 years.
• Whole body aging slowed by about 1.0 to 1.3 years.
• Immune system aging slowed by about 0.6 years.
• Liver aging slowed only after 24 months, and kidney aging was not affected.
• People who cut calories more (at least 12.4%) saw greater slowing in metabolic and whole body aging.

How much to trust it

This is a randomized controlled trial, which is a strong design for a single human study, so it earns a 'Good' trust tier. The main limitation is that it is one study, and the results may not apply to everyone.

Your action plan

• Consider reducing portion sizes gradually to lower daily calorie intake, if your doctor agrees.
• Focus on nutrient-dense foods like vegetables, fruits, and whole grains to stay healthy while eating less.
• Track your eating habits for a week to see where you can trim extra calories.
• Discuss any major diet changes with a healthcare professional.

This summary is for general information only and is not medical advice. Talk to a qualified professional before changing anything about your health.

Source

Effect of caloric restriction on organ-specific biological aging in a randomized clinical trial.. Clinical nutrition (Edinburgh, Scotland). 2026 PubMed