"the Mediterranean diet to be the healthiest" - and here am I, yet again, pointing out that this is because it is high in monounsaturated fat (MUFA), which also helps with belly-fat loss, and I wrote about here https://dotnet.social/@SmartmanApps/111424121243237697.
"multiple servings of fruits and vegetables daily, alongside whole grains, legumes, nuts, olive oil and seafood" - those last 3 are all foods which are high in MUFA, in particular olive oil (and other oils), macadamias, almonds, peanuts, and fatty fish.