Time and over again, the benefits of a low-calorie diet have been argued. It has now been found that indulging in a low-calorie diet can retard the ageing process. Although studies conducted on animal models show promising results, conducting human studies have proven to a challenging task.
However, a study by the Washington University School of Medicine in St. Louis, Missouri, and the Italian National Institute of Health in Rome shows that restricting calorie intake coupled with optimal nutrition may delay primary aging in humans, science portal world-science.net reported.
The study, to appear in the Jan 17 issue of the Journal of the American College of Cardiology, claims to be the first to associate a low calorie diet with delayed signs of aging in humans.
The researchers compared 25 people who had already been following caloric restriction for an average of six years, consuming about 1,400 to 2,000 calories a day, with 25 similar control subjects who were eating typical Western diets, about 2,000 to 3,000 calories a day.
Hearts tend to stiffen and pump less effectively as people get older, but ultrasound examinations showed that the hearts of the people on caloric restriction appeared more elastic than those of the control subjects; that is, the hearts relaxed between beats in a way that is similar to the hearts of younger people.
In addition, several heart disease risk factors and inflammatory markers were lower in the caloric restriction group than in the Western diet group.
Luigi Fontana, who designed and led the study, emphasised that caloric restriction does not mean simply eating less.
"Calorie restriction is associated with longevity only when it is coupled with optimal nutrition. On the other hand, calorie restriction coupled with malnutrition accelerates aging and causes severe diseases.
"Therefore, eating half a hamburger, half a bag of French fries and half a can of soft drink is not healthy caloric restriction and is harmful," he said.
The caloric restriction model requires a strict diet regimen, both to keep the total number of calories low and to ensure that participants consume the right balance of nutrients, he said.