CHINA - In line with the old saying that a good diet cures more than a doctor, people have believed for some time that eating less can preserve health and extend life span.
But there has been little scientific evidence to show how cutting back on the calories can help.
However, scientific research published in Nature Communications on Tuesday could provide a new explanation. Calorie restriction promotes the growth of gut bacteria associated with increased life span in mice, according to a news release from the science magazine.
Chinese researchers gave mice high-fat and low-fat foods - some were given as much food as they wanted (free-feeding), while others were under calorie restriction (given only 70 per cent of the food of the free-feeding group).
The results showed that the calorie-restricted low-fat group lived the longest, while the mice that ate as much high-fat food as they wanted had the shortest lives.
Analysis of the mice faeces showed that some beneficial bacteria correlate positively with life span and are enriched by calorie restriction, while bacteria that correlate negatively with life span are reduced by the restriction, the news release said.
"Scientific research has been pointing to the result that calorie restriction increases life span, but the unanswered questions are why and how," said Zhao Liping, a professor specialising in microbiology at Shanghai Jiao Tong University, who led the research.
"So this research provides a new angle to explain the relationship between calorie restriction and life span - that calorie restriction might take effect via altering gut bacteria," he said.