Gaby
A team of researchers at the Jackson Laboratory in the U.S., led by Professor Gary Churchill, says the secret to a long life lies more in our genes than in fasting.
This conclusion comes from a large-scale experiment involving nearly 1,000 female mice. The study also showed that while fasting can help extend life, cutting calories doesn’t benefit everyone the same way.
Previous research has suggested that eating fewer calories is linked to a longer, healthier life. Scientists have shown, for instance, that a 25 percent reduction in calories can slow the aging process by about 3 percent.
What the Researchers Discovered
In the study, the researchers tested the effects of intermittent fasting and caloric restriction in nearly 1,000 female mice. The rodents were divided into five groups based on the type of diet the scientists assigned.
The first group could eat freely at any time. The second and third groups were given 60 percent and 80 percent of baseline caloric intake, respectively. The last two groups fasted for one or two days each week, and on the other days they could eat as much as they wanted.
The researchers monitored the mice throughout their lives, measuring about 200 metrics, including body weight, body fat, and blood glucose levels.
The team found that mice with unrestricted diets lived an average of 25 months. Those on intermittent fasting lived about 28 months on average. Mice receiving 80 percent of their food lived to roughly 30 months, while those on a 60 percent diet reached an average of 34 months.
The researchers found that caloric restriction often increased lifespan. But lifespans varied a lot within each group. For example, in the group consuming the fewest calories, lifespans ranged from a few months to four and a half years.
After digging into why the range was so wide, the scientists concluded that genetic factors had a bigger impact on lifespan than diet. Although fasting often promoted longevity, it wasn’t the only factor.
Professor Churchill said, “The strongest animals maintain their weight even under stress and caloric restriction, and they are the ones that live the longest.”
He also suggested that a moderate level of caloric restriction could help “balance long-term health and lifespan.”
Key Takeaways
The study’s authors say genes play a major role in how diet affects an individual’s health trajectory.
Professor Churchill joked, “If you want to live a long time, there are things you can control throughout your life, like your diet, but really, you need a very old grandmother.”
He added, “While caloric restriction is generally beneficial for longevity, our data show that weight loss during caloric restriction can actually be detrimental to lifespan.”
So, Churchill said, when people lose weight and improve their metabolism during trials of longevity drugs, that doesn’t necessarily predict their future lifespan.
The team emphasized the need for more research in humans to clarify the impact of restrictive diets on lifespan, including intermittent fasting and caloric restriction while maintaining adequate nutrient intake.
