Adults at a healthy weight who cut around 300 calories a day could significantly improve their blood glucose levels and lower their type 2 diabetes risk, research suggests. This calorie reduction also led to improvements in cholesterol profile, blood pressure and other health markers. The Duke University Health System conducted the trial to build on the hypothesis that it's not just weight loss that leads to health improvements, but a more complex change in the metabolism caused by eating fewer calories. The researchers randomised 218 adults under the age of 50 with healthy BMI levels to either eat their normal diet or eat three meals a day while cutting one-fourth of their daily calories. The calorie restriction group were also provided all three of their daily meals for a month while they learned about the basics of cutting calories. The study ran for two years, with participants lowering their calorie intake by choosing from six different meals plans that accommodated cultural preferences or dietary requirements. Participants also attended group and individual counselling for the first six months of the trial. Despite being instructed to restrict calories by 25%, the average calorie reduction among the calorie restriction group after two years was around 12%, equal to 300 calories. This group sustained a 10% drop in weight, 71% of which was fat. They also experienced improvements in markers of metabolic disease, heart disease, cancer 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," said lead author William E. Kraus, M.D., a cardiologist at Duke Health. "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." The researchers do not fully understand the mechanisms behind the improvements, but have already begun tests exploring the results. "There's something about caloric restriction, some mechanism we don't yet understand that results in these improvements," said Kraus. "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." The findings appear in The Lancet Diabetes and Endocrinology.