Although fasting diets have been criticised by nutritionists for being unhealthy, new research suggests starving the body kick-starts stem cells into producing new white blood cells, which fight off infection.
Scientists at the University of Southern California say the discovery could be particularly beneficial for people suffering from damaged immune systems, such as cancer patients on chemotherapy.
It could also help the elderly whose immune system becomes less effective as they age, making it harder for them to fight off even common diseases.
The researchers say fasting "flips a regenerative switch" which prompts stem cells to create brand new white blood cells, essentially regenerating the entire immune system.
Interesting Maybe that's why you don't have an appetite when you're sick...