This review aims to quantitatively define the Mediterranean diet (MedDiet) based on food groups and nutrients. The MedDiet is characterized by high intake of vegetables, fruits, cereals, and olive oil, with moderate intake of fish, dairy, and red wine, and low intake of eggs and sweets. The review analyzed multiple studies and found that the MedDiet contains approximately 9300 kJ per day, with 37% as total fat, 18% as monounsaturated fat, 9% as saturated fat, and 33 g of fiber daily. The MedDiet includes 3–9 serves of vegetables, half to two serves of fruit, one to 13 serves of cereals, and up to eight serves of olive oil daily. The review also found that the MedDiet has a high content of polyphenols, including flavonoids, which are associated with various health benefits. However, there is considerable variation in the definitions and quantities of the MedDiet across different studies, which may affect the interpretation of health outcomes. The review suggests that a more consistent and standardized definition of the MedDiet is needed to improve the understanding of its health benefits and to guide future research and dietary recommendations. The review also highlights the importance of considering nutrient content rather than food quantities when defining the MedDiet, as this approach may provide a more accurate representation of its health benefits. The study concludes that the MedDiet has the potential to improve cardiovascular and cognitive health, and that a more consistent and standardized definition is necessary to fully understand its benefits and to guide future dietary recommendations.This review aims to quantitatively define the Mediterranean diet (MedDiet) based on food groups and nutrients. The MedDiet is characterized by high intake of vegetables, fruits, cereals, and olive oil, with moderate intake of fish, dairy, and red wine, and low intake of eggs and sweets. The review analyzed multiple studies and found that the MedDiet contains approximately 9300 kJ per day, with 37% as total fat, 18% as monounsaturated fat, 9% as saturated fat, and 33 g of fiber daily. The MedDiet includes 3–9 serves of vegetables, half to two serves of fruit, one to 13 serves of cereals, and up to eight serves of olive oil daily. The review also found that the MedDiet has a high content of polyphenols, including flavonoids, which are associated with various health benefits. However, there is considerable variation in the definitions and quantities of the MedDiet across different studies, which may affect the interpretation of health outcomes. The review suggests that a more consistent and standardized definition of the MedDiet is needed to improve the understanding of its health benefits and to guide future research and dietary recommendations. The review also highlights the importance of considering nutrient content rather than food quantities when defining the MedDiet, as this approach may provide a more accurate representation of its health benefits. The study concludes that the MedDiet has the potential to improve cardiovascular and cognitive health, and that a more consistent and standardized definition is necessary to fully understand its benefits and to guide future dietary recommendations.