Study Finds Eating Fewer Calories Better than Intermittent Fasting for Extending Lifespan

A new study conducted by researchers at The Jackson Laboratory sheds light on the complex relationship between diet, genetics, and lifespan. The research, published in Nature, involved nearly 1,000 genetically diverse mice on various diets, providing a more accurate representation of human genetic diversity. 

The study found that calorie restriction had a more significant impact on lifespan than intermittent fasting. Surprisingly, mice that maintained their weight while on restrictive diets lived the longest, challenging the notion that weight loss is always beneficial for longevity.

As Gary Churchill, senior author on the paper, noted, "The most robust animals keep their weight on even in the face of stress and caloric restriction, and they are the ones that live the longest."

Mice on unrestricted diets lived an average of 25 months, while those on the most restrictive diet (60% of baseline calories) lived an average of 34 months. However, lifespans within each group varied widely, highlighting the importance of genetic factors in determining longevity.

The research also questioned traditional markers of aging and health. Factors such as weight, body fat percentage, and blood glucose levels were not strongly linked to increased lifespan. Instead, immune system health and red blood cell-related traits showed clearer connections to longevity.

Churchill emphasized the significance of resilience in the aging process: "If you want to live a long time, there are things you can control within your lifetime such as diet, but really what you want is a very old grandmother."

This study provides valuable insights for human longevity research, suggesting that current metabolic measurements used as markers for aging may be overlooking more critical aspects of healthy aging. “While caloric restriction is generally good for lifespan, our data show that losing weight on caloric restriction is actually bad for lifespan,” Churchill explained. “So when we look at human trials of longevity drugs and see that people are losing weight and have better metabolic profiles, it turns out that might not be a good marker of their future lifespan at all.”