But Mackerel is fatty, rich flavored, moist and so sweet that it is almost requisite to cook it with acidic flavors such as lemon or tomato. It is the mackerel's fat that has given it such a bad reputation. But sirloin steak has a high fat content too. And, unlike steak, mackerel is high in omega 3s and low in cholesterol. The English prefer mackerel smoked, the Japanese and French pickle it, and the Greeks dry it in the wind. All of these excellent treatments are rather old-fashioned ways of preserving a fragile fish. It is exceptional to broil a whole mackerel, and also just as nice to grill it. You can also poach or roast fillets.