A lot of abdominal programs and fat loss programs talk about the same old stuff; about how much protein we should eat, how many carbs, what are the breakdown of nutrients, how many calories, blah, blah, blah. It's not a sustainable way of looking at food and food is not meant to be broken down in that way. I am all about eating more whole, plant based foods.
The most important substance you can get from fatty fish is omega-3.