Postprandial Glucose Kinetics After Carbohydrate Restriction

The goal of this study is to test whether a low-carbohydrate diet (LCD), comparred with a Mediterranean diet (MED) producing similar weight loss, differentially affects fasting and postprandial glucose metabolism in individuals with overweight and dysglycemia. The main questions it aims to answer are: * Is oral glucose absorption delayed or reduced after chronic carbohydrate restriction? * Is insulin sensitivity differentially affected? Participants will follow 4 weeks of LCD and 4 weeks of MED, in a random order, separated by a 4-week washout. After each intervention, participants will undergo a dual-tracer 75-g oral glucose tolerance test.