Despite the many well-documented benefits of the Mediterranean diet (MD), many Mediterranean countries seem to be moving away from it. The aim of this study was to investigate the MD adherence in 10,916 adults who completed the validated Medi-Lite questionnaire from January 2019 to December 2022 in Italy, and to assess the consumption of its food groups by comparing them with current national dietary guidelines. The sample showed a good level of MD adherence (12 ± 2.5). However, from 2019 to 2022, a significant ( < 0.001) decline in the adherence level emerged. An overconsumption of fresh red meat, cheese and poultry compared to dietary guidelines was observed. In contrast, an under-consumption of vegetables, bread, legumes, fish and milk and dairy products emerged. In recent years, a decline in MD adherence was observed in Italy, probably determined by an excessive consumption of animal products.