If results of a preliminary study in humans are to be believed, reducing calories may well extend life. This was found out as part of a research which appears in this week's Journal of the American Medical Association.
In a statement by co-author Dr. Eric Ravussin, from Louisiana State University in Baton Rouge, "A lot of evidence already exists to suggest that calorie restriction increases maximum life span in several animal species. However, there hasn't been any proof of it being the case in humans. This is the first step toward looking at the beneficial effects of calorie restriction in humans."48 healthy overweight (but not obese) men and women in a 6-month trial were enrolled for the study and the effects of calorie reduction on their health were studied.
Participants were assigned to one of four groups: a control group, which followed a normal diet; a calorie restriction group ( 25 percent less calories than the daily requirement); a third group, which exercised and reduced calorie intakes (12.5 percent calorie restriction and 12.5 percent increase in energy expenditure); or a group that received a very low calorie diet, starting with 890 kcal a day and then increased to maintain a 15 percent weight loss.
The results were that the control group lost about 1 percent of their weight, both calorie restriction groups (with or without exercise) lost approximately 10 percent. Individuals on the very low-calorie diet lost nearly 14 percent of their weight.
Ravussin put the results as follows,” Body temperature and blood insulin levels are markers of longevity like gray hair or wrinkles can be. It has been shown both in animals and humans that those with lower body temperature tend to live longer, and so do those with lower fasting insulin levels. One of the many theories of aging is that there is more DNA damage happening, which is the destruction of genetic information -- smokers for example have more DNA damage. So this is very important information, totally novel in humans, that calorie restriction can reduce DNA damage."
