Mice live longer and are healthier in old age if they are given 40 per cent less to eat after reaching adulthood than animals who are allowed to eat as much as they want. The dieting mice are fed with food enriched with vitamins and minerals to prevent malnutrition. But if food intake is first reduced in mice first start eating less food when they are already seniors, the researchers observe little or no effect on the life expectancy of the mice.
On the other hand, when mice are allowed to eat as much as they like after a period of reduced food intake, they have no long-term protection, so reduced food intake has to be sustained for mice to reap the benefits.
Reduced food intake must, therefore, be implemented early and be sustained until the end of their lives to have positive effects on health in old age. “One should establish healthy behaviours early in life. It may not be as good for your health to change your diet later in life. Health in old age is a lifelong affair”, explains Linda Partridge from the Max Planck Institute for the Biology of Ageing and UCL.