Why we age more slowly if we eat little

There's a lot of talk about longevity, about how life is getting longer, and about research focused on new drugs that can help both eradicate diseases that are still fatal today and slow down the cellular deterioration associated with advancing age. 

But scientists agree on another point: to live longer, especially as we age, we need to reduce food intake and eat little and often. And where does this relationship between moderate meals and longer life come from?

First of all, food restriction translates into a caloric restriction that allows the body to "repair" cells and ensure they can reproduce longer, without disappearing. Research shows that calorie restriction activates genes and cellular processes, such as autophagy, that can protect the body from stress and premature aging. Autophagy (a scientific term derived from the Greek and meaning "self-eating") is a natural mechanism by which cells, when degraded, are able to recycle their own components, thus enabling them to survive longer. We could define it as a natural maintenance process in our body, without drugs or therapies, but only based on a healthy and moderate diet. The equation is this: fewer calories, greater longevity.

The most important study dates back to 2024, edited by a group led by Gary Churchill (and which also included the Italian Andrea De Francesco), published on Nature, studied 960 genetically diverse mice, assigning them to five dietary regimes:

• free-range feeding
• fasting 1 day a week
• fasting 2 days a week
• 20% calorie restriction
• 40% calorie restriction

The main results were:

• Calorie restriction increased lifespan proportionally to calorie reduction
• the group with 40% restriction had the greatest increase in longevity

A previous study, of 2022, entitled CALORIE (Comprehensive Assessment of Long-term Effects of Reducing Energy Intake), reaches very similar and equally important conclusions, while maintaining the importance of the genetic component in matters of longevity. 

The participants followed for 2 years a caloric restriction of approximately 12-14% (less than the 25% initially expected).

The results showed:

• improvement of blood pressure;
• improved insulin sensitivity;
• reduction of inflammation;
• changes in the expression of genes involved in DNA repair, autophagy, and mitochondrial function;
• slowdown of some indicators biological age. 

A further reduction in calories, ensured by a moderate diet, is associated with a significantly lower risk of obesity and overweight, with related problems of cardiovascular disease, neurodegenerative diseases, and diabetes. With a moderate but nutritionally complete diet,Calorie restriction helps reduce blood pressure, lower cholesterol and triglycerides, decrease visceral fat (the fat that accumulates around the organs), and contain chronic inflammation and oxidative stress. 

Read also: 

• How to age well
• How to Live After 60
• How not to fall when you are old