One of the counter intuitive things about losing fat is that you need to eat certain fats to help lose other fats.
So called healthy fats are essential for your body, and help all sorts of processes take place inside the body. You could not survive without these fats.
What you need to do, and where many people fall down, is in the type of fat that you eat.
Those that are beneficial in the right quantity have strange names like mono and polyunsaturated fats, like olive oil, sunflower oil and that which is in avocados.
In contrast, those that you should avoid are trans fat and hydrogenated (partially) oils.