Found this today on the BBC News site. Once again greed and laziness over-ride the obvious answers...:

Food formula 'increases lifespan' 

A formula added to food could have the potential to extend the lives of obese people by 20%, scientists believe. 
Finnish researchers found the formula of plant sterols and mineral nutrients extended the lives of obese rats by 60% when it was mixed with fatty food. 
The increase in lifespan was caused by the composition lowering cholesterol and blood pressure levels, the team at the University of Helsinki said. 
But experts said rat studies did not always transfer well to humans. 
The benefits of plant sterols, which are added to some margarines, are already known. 
But the scientists said it was the combination of the sterols and the nutrients - calcium, potassium and magnesium - which had an effect. 

The team found the rats which were fed high-fat, high-salt diets with the enrichment formula, given the name MultiBene, lived longer than those which were not. 
It is thought the formula helped improve the function of blood vessels. 
The formula also helped to combat obesity but the effect was not as "surprising" as the increase in lifespan. 
Professor Heikki Karppanen, the lead adviser on the study, said while he did not think the 60% figure could be repeated in humans, 20% could easily be achieved........


http://news.bbc.co.uk/1/hi/health/3987199.stm

Cheers,

Persephone