We would probably live longer if we ate less

Animal research shows that calorie restriction can prolong life. In many animal species, from yeasts to rodents and primates, a diet 20-40% lower in calories leads to much longer lifespans, sometimes 30-50% longer.

The exact mechanisms are not yet fully elucidated, but factors such as decreased oxidative stress, improved insulin sensitivity, and activated autophagy (cell healing) may play a role.

Experts also discuss

We're still talking about how it works, and whether the number of calories consumed or the time period over which they are eaten (aka intermittent fasting) is more important.

Human studies

• Long-term studies of strict caloric restriction in humans are rare due to practical and ethical challenges. You can't let thousands of people starve for thousands of years without knowing if it will lead to anything.
• Some short-term studies show beneficial effects on biomarkers of aging, but the effect on actual life extension is unknown.
• Intermittent fasting, a form of periodic calorie restriction, appears to offer some health benefits, but long-term effects are still unclear.
• In general, experts point out that restricting calories may prolong life, but following a balanced diet and healthy lifestyle is just as important.

Although calorie restriction appears promising based on animal studies, more long-term research in humans is needed to determine its effects on extending life. A healthy, varied diet combined with other lifestyle factors such as exercise seems to be the best approach to a long and healthy life.