Researchers have published an interesting set of results from one of a number of human studies of moderate calorie restriction that have taken place over the past decade. Reduced calorie intake has a beneficial effect on long-term health, producing outcomes in human and animal studies that no presently available medical technology can match, because no presently available medical technology slows progression of the cell and tissue damage that causes aging to the same breadth and degree. That is all the more reason to put more effort into producing therapies capable of treating these causes of aging, but why not take advantage of benefits that are free while waiting for rejuvenation therapies to arrive? There is some speculation as to the degree to which benefits resulting from calorie restriction are due to carrying around less visceral fat, tissue that contributes to chronic inflammation, but research demonstrates that there is a lot more than that going on. Calorie restriction moves almost all measures of metabolic activity, and among many other things spurs greater cellular housekeeping activities, for example.
A 25 percent calorie restriction over two years by adults who were not obese was linked to better health-related quality of life, according to the results of a randomized clinical trial. Researchers tested the effects of calorie restriction on aspects of quality of life that have been speculated to be negatively affected by calorie restriction, including decreased libido, lower stamina, depressed mood and irritability. Their work extends the literature with a study group of nonobese individuals because beneficial effects of calorie restriction on health span (length of time free of disease) increase the possibility that more people will practice calorie restriction.
In this clinical trial conducted at three academic research institutions, 220 men and women with body mass index of 22 to 28 were enrolled and divided almost 2 to 1 into two groups: the larger group was assigned to two years of 25 percent calorie restriction and the other was an ad libitum (their own preference) control group for comparison. The analysis included 218 participants and self-report questionnaires were used to measure mood, quality of life, sleep and sexual function. Data were collected at baseline, a year and two years. Of the 218 participants, the average age was nearly 38 and 70 percent were women. The calorie restriction group lost an average of 16.7 pounds compared with less than a pound in the control group at year two.
According to the authors, the calorie restriction group, compared with the control group, had improved mood, reduced tension and improved general health and sexual drive and relationship at year two, as well as improved sleep at year one. The bigger weight loss by the calorie restriction participants was associated with increased vigor, less mood disturbance, improved general health and better quality of sleep. "Calorie restriction among primarily overweight and obese persons has been found to improve quality of life, sleep and sexual function, and the results of the present study indicate that two years of calorie restriction is unlikely to negatively affect these factors in healthy adults; rather, CR is likely to provide some improvement."