Eat less, look younger? Well, it's not quite that easy, but there is new research on calorie restriction and aging. Weight management is harder for older adults, but reducing caloric intake will impact more than just weight.
A study published recently looked at older adults who reduced the number of calories consumed by 15% over a two year period. The focus of the research was not just weight loss, but rather metabolism. When the body absorbs fewer calories, the cell metabolism slows down. In turn, there was less oxidative stress overall. Many neurobiological conditions like Alzheimer's disease and Parkinson's are linked directly to cellular oxidative stress. It's not just neurological conditions either. Some forms of cancer, as well as diabetes, are connected to the same kind of cellular stress.
Lead author of the work, Leanne M. Redman is an associate professor of Clinical Sciences at Pennington Biomedical Research in Baton Rouge. She explained, "Restricting calories can slow your basal metabolism, and if by-products of metabolism accelerate aging processes, calorie restriction sustained over several years may help to decrease risk for chronic disease and prolong life."
The work, dubbed CALERIE (Comprehensive Assessment of the Long-Term Effects of Reducing Intake of Energy) was a randomized controlled trial investigating how calorie restriction would impact metabolism in patients who were not obese. Fifty-three healthy adults from age 21 to age 50 took part. Over a span of two years, the participants reduced their calories consumed by 15%. Each patient had specific measurements of their caloric intake so the reduction numbers could be accurate. The volunteers also underwent metabolic testing and other assessments that measured oxidative stress.
While it was not the goal, the calorie restriction did result in an average weight loss of about 9kg, but patients had not followed any specific diets or changed their fitness habits. While it wasn't necessary for their health, most participants did report feeling better physically and mentally. The authors stressed that while most studies that involve restricting calories are on weight loss, their project was explicitly about growing older. Redman stated, "We know from mammalian studies that the smaller the mammal, the faster their metabolism and the shorter their longevity." While a slower metabolism in a weight loss focused goal isn't optimal, regarding the aging process, slower is better.
The study was small, so a more extensive work is planned as well as research into biomarkers that can more definitely pinpoint where a person is in the aging process. Redman summarized what the results meant, writing, "The CALERIE trial rejuvenates support for two of the longest-standing theories of human aging: the slow metabolism 'rate of living' theory and the oxidative damage theory." Check out the video below to hear more.