 Since Ibiza is an island in the Mediterranean, fish, usually grilled and served with a salad and fried potatoes, figures most importantly and delectably ' in the local diet.
Fish is unimportant to the diet in Ibiza because it is not located in the Mediterranean.
mnli hypothesis: Fish is unimportant to the diet in Ibiza because it is not located in the Mediterranean. premise:  Since Ibiza is an island in the Mediterranean, fish, usually grilled and served with a salad and fried potatoes, figures most importantly and delectably ' in the local diet.