There's nothing wrong with a "Mediterranean Diet" for fat loss, but you will still need to count calories and make an effort to eat less than you burn. However if you are insulin resistant to some degree due to following a typical western diet for too long, then you may find the Mediterranean Diet is too high in carbs and too low in protein for optimal fat loss. In other words, it may be a great lifestyle diet to prevent obesity, but it may not be so great once you've already put on the fat. And remember, it IS a lifestyle, not a diet.