Just cutting 300 calories a day is all that is necessary to reduce the risk of cardiovascular disease even in lean people, it establishes the clinical trial.
Duke Health's two-year experience shows that when it comes to reducing the risk of killer diseases such as diabetes and heart disease, there is always room for improvement. The results of the randomized, controlled clinical trial have appeared in the journal Diet and Endocrinology of Lancet.
The clinical trial, part of an ongoing project with the National Institute of Health CALERIE, continues to be based on the researchers' hypothesis that not only weight loss leads to these improvements, complex metabolic changes caused by consuming fewer calories than what is being consumed.
For adults already with healthy weight or just a few extra pounds, cutting about 300 calories a day significantly improves already good cholesterol levels, blood pressure, blood sugar and other markers.
"There's something about limiting calories, some mechanism we do not yet understand, which leads to these improvements," says lead study author William Kraus, a cardiologist and prominent professor of medicine at Duke. "We have collected blood, muscles, and other samples from these participants and we will continue to investigate what this metabolic signal or magical molecule might be."
For the first month of the clinical trial, participants ate three meals a day that would reduce one quarter of their daily calories to train them on the new diet. They can choose from six different eating plans that are tailored to cultural preferences or other needs. Participants also attended group and individual consultations during the first six months of the trial, while the control group members simply continued their usual diet and met with researchers once every six months.
Participants were asked to maintain a 25 percent reduction in calories in two years. Their ability to do so varies, with an average calorie reduction for all participants of about 12%. Still, they managed to withstand a 10% drop in weight, 71% of whom were fat, the study found. There are numerous improvements in markers that measure the risk of metabolic diseases. After two years, participants also showed a decline in the biomarker, which shows chronic inflammation, which is also associated with heart disease, cancer and cognitive decline.
"This shows that even a modification that is not as severe as what we used in this study can reduce the burden of diabetes and cardiovascular disease that we have in this country," Krauss said. "People can do this relatively easily, just by watching their little imprecision here or there, or maybe reducing their amount by not breaking after dinner."