How much can human life span be extended

When molecular biologists began researching ways to extend the life span, theyfound that reducing the activity of insulin-like receptor doubled the life expectancy of worms and that certain strains of mice put on a near-starvation but nutrient-rich diet lived 50% longer than normal. However, these strategies may not work on humans, and even if life spans were extended demographers believe that slowing aging would have profound social effects.