The results of a two-year study from Duke Health show even among those in a healthy weight range there is a benefit to reducing calories. It confirmed the thinking there is always room for improvement when it comes to cutting the risk for heart disease and diabetes.
The report released in the journal The Lancet Diabetes & Endocrinology detailed how the reduction of 300 calories per day led to a great improvement on already healthy markers related to blood pressure, blood sugar, cholesterol and others.
The randomized, controlled trial included 218 adults under the age of 50 and was part of an ongoing project with the National Institutes of Health called CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy). The purpose of the project is to continue researching evidence regarding the hypothesis that it is more than just weight loss responsible for the improved health markers. They believe there are more complex metabolic changes happening as a result of eating fewer calories than those expended by the body.
"There's something about caloric restriction, some mechanism we don't yet understand that results in these improvements," said the study's lead author William E. Kraus, M.D., 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 this metabolic signal or magic molecule might be."
Participants ate three meals a day designed to cut 25 percent of their calories for the first month to help train them on the new diet. They had six different meals plans to choose from to accommodate different tastes and other preferences. They also attended individual and group counseling sessions for the first six months. At the same time, those in the control group continued their regular diet and met with researchers every six months.
Study participants were asked to keep up their calorie-restricted eating for two years. Not all were able to keep up the entire 25 percent reduction during that time. The average for all participants was a 12 percent reduction.
However, the results showed they were able to sustain a 10 percent drop in weight. And 71 percent of that weight was fat. Other improvements included markers related to the risk for metabolic disease. One was a drop in the biomarker indicating chronic inflammation, which has been linked to cancer, heart disease and cognitive decline.
"This shows that even a modification that is not as severe as what we used in this study could reduce the burden of diabetes and cardiovascular disease that we have in this country," Kraus said. "People can do this fairly easily by simply watching their little indiscretions here and there, or maybe reducing the amount of them, like not snacking after dinner."