There is bad news for middle-aged people who love to eat lots of meat, milk and cheese. They are four times more likely to die of cancer than someone with a low-protein diet, said researchers.

 

 Those who eat lots of protein from animal sources are also more susceptible to early death in general. "Protein-lovers were 74 percent more likely to die of any cause within the study period than their more low-protein counterparts," said a study. People on high animal protein-rich diet were also several times more likely to die of diabetes.

 

 "The research shows that a low-protein diet in middle age is useful for preventing cancer and overall mortality, through a process that involves regulating IGF-I (a growth hormone controlled by protein) and possibly insulin levels," said Eileen Crimmins, professor of gerontology at the University of Southern California.

 

 "However, we also propose that at older ages, it may be important to avoid a low-protein diet to allow the maintenance of healthy weight and protection from frailty," Crimmins said. People need to switch to a diet where only around nine or 10 percent of their calories come from protein, and the ideal sources are plant-based.

 

 The study, published in the Cell Metabolism journal, found that plant-based proteins such as those from beans did not seem to have the same mortality effects as animal proteins.