Even in slender adults, cutting around 300 calories a day protects the heart

New data from a two-year trial conducted by Duke Health suggest that to reduce the risk of life-threatening conditions such as diabetes and heart disease, there is always room for improvement.

In adults who already have a healthy weight or are just a few pounds off, the reduction of 300 calories a day has dramatically improved cholesterol levels, blood pressure, blood glucose and other already satisfactory markers. The results of the randomized controlled trial of 218 adults under 50 are described in a July 11 article in the journal. The Diabetes Lancet & Endocrinology.

The trial, which is part of an ongoing project with the National Institutes of Health called CALERIE (full evaluation of the long-term effects of the reduction of energy absorption), continues to build on the researchers' hypothesis that it's not just weight loss that drives these improvements but some more complex metabolic changes triggered by consuming fewer calories than what is spent.

"There is something about caloric restriction, a mechanism that we do not yet understand that leads to these improvements," said lead author William E. Kraus, MD, a cardiologist. and distinguished professor of medicine at Duke. "We have collected blood, muscle and other samples from these participants and will continue to explore what could be this metabolic signal or this magic molecule."

During the first month of the trial, participants took three meals a day, which would reduce a quarter of their daily calories to help them become familiar with the new diet. They could choose from six different meal plans, tailored to cultural preferences or other needs. Participants also attended individual and group counseling sessions during the first six months of the trial, while members of a control group simply continued their usual diet and met with researchers a once every six months.

Participants were asked to maintain the 25% reduction in calories for two years. Their ability to do this varied, the average calorie reduction for all participants being about 12%. Still, they managed to maintain a 10% weight loss, including 71% fat. There have been many improvements in markers that measure the risk of metabolic disease. After two years, participants also showed a reduction in a biomarker that indicates chronic inflammation that has also been linked to heart disease, cancer, and cognitive decline.

"This shows that even a less severe modification than we used in this study could reduce the burden of diabetes and cardiovascular disease in our country," Kraus said. "People can do it quite easily by just looking at their little indiscretions here or there, or maybe reducing the number, like not nibbling after dinner."

For example, six Oreo calories represent 300 calories.