Stay Hungry, Says New Study Of Longevity

Eat less, live longer.

This sad rule has long been known to be true for lab rats. But now scientists are beginning to show that higher animals - perhaps even people - also may live longer and better if they stop eating before they feel full.

The theory is that lowering calories resets the body’s metabolism so it operates more efficiently.

“It’s like driving your car at a slower speed,” said Dr. George Roth. Car engines typically last longer at 50 mph than at 80.

For 60 years, researchers have observed that holding back on food significantly extends the lives of various kinds of bugs, worms and rodents in the laboratory. But proving the same is true for people is next to impossible. No one would voluntarily go on a carefully controlled low-cal diet for many decades.

So for the past 10 years, researchers from the National Institute on Aging in Bethesda, Md., have been doing this experiment on the closest thing to people they can find - rhesus and squirrel monkeys.

And while it’s still too soon to know if the underfed animals will live longer, Roth presented evidence Friday that they seem healthier. In a report at a meeting of the American Association for the Advancement of Science, Roth showed the calorie-restricted monkeys have lower blood pressure and better cholesterol levels.

In the experiments, conducted on about 200 animals, half can eat as much as they want, while the rest get 30 percent less. The food is fortified with vitamins and minerals.

“It is undernutrition without malnutrition,” Roth said.

Last year, he and colleagues published a report showing that monkeys on the low-calorie diet had lower body temperatures.

Perhaps the most striking of the latest data is that the underfed animals look as though they will be protected from heart disease. Their levels of high-density lipoprotein - the good cholesterol that helps keep blood flowing - are twice as high.

Furthermore, the dieting monkeys’ blood fats are down, and their blood pressures are 5 percent to 10 percent lower.

Roth said he believes that in the end, it will turn out that calorie restriction will help people live longer, as well. He speculated that it might be possible to add 20 or 30 years onto the typical human lifespan of 80 or so years.