research: fly bites dogma

3 October 2005

A study from Linda Partridge and colleagues at University College London questions the widely held belief that low food intake (so-called dietary restriction) extends lifespan simply by reducing calorie intake.

Many studies have shown that near-starvation levels of nutrition can significantly extend lifespan. Professor Partridge's study looked more closely, to see if the type of nutrition – rather than just the number of calories consumed – was important.

By reducing the amount of either sugar or yeast in the food fed to fruit flies, the researchers could remove the same number of calories. The extension of lifespan was much more marked when yeast intake was reduced – suggesting that, in flies at least, the type of food consumed is critical, rather than simple calorie intake.

Mair W et al. Calories do not explain extension of life span by dietary restriction in Drosophila. PLoS Biol 2005;3(7):e223.