Going hungry helps lab animals live longer, but for people like you and me, living in the real world, may have the opposite effect, warns Jacob Aron
Thin herbs: starving yourself could make you more prone to infections than a diet with fats
The idea that severely reducing your caloric intake will help you live longer may not be as simple as reports last week suggested. Eating a radically restricted diet can weaken the immune system and actually shorten life.
While "eating less" has been shown to delay the aging process in a variety of animals, these tests are usually conducted under artificial conditions with little or no exposure to diseases potentially related to a fat diet. Hence the apparent contradiction.
The study "slowing down the aging process through diet began early in 1934, when researchers at Cornell University found that rats given a restricted diet can live nearly double the normal time. Restriction to calories as a pathway to a longer life has been confirmed in fruit flies, roundworms and most recent studies done with monkeys, but all of these studies keep animals in artificially clean environments.
Scientists at Stanford University today published a more realistic approach to calorie restriction in the journal PLoS Biology. Associate Professor of Microbiology and Immunology David Schneider and undergraduate student Janelle Ayres worked with fruit flies, this time to investigate the effects of bacterial infections on organisms with a restricted diet.
They found that eating less can increase or shorten the life of infected flies, depending on the disease. Flies that were given half their normal diet and exposed to a form of salmonella infection lived almost twice as did their siblings on a fatty diet, which lasted only eight days after infection. But when infected with listeria, another intoxication bug, the "lean" diet flies died after only four days, compared to the six or seven flies that fed normally.
In one study, the authors suggest that this mixed reaction to infections should raise a flag of warning to those who wish to live longer by eating less.
Although the effects of calorie restriction on humans have yet to be proven, people have been tempted to reduce their food intake radically with the prospect of a few more years to come. The latest research suggests that this may work if you live in a sterile laboratory and meanwhile for those of us living in the real world, full of bacteria, should probably get into the habit of a healthier diet.
Translated from English into Original Eat up! Calorie restriction may weaken the immune system by Cláudio Souza on 13 / 06 / 2015