In recent years, dietary fat has gained a very bad reputation. Health conscious folks limit their fat intake to the point it can actually be damaging to their health. I honestly do not believe in ultra low-fat diets. A certain amount of fat is necessary for the proper brain development in infants and children. It is needed for the formation of the myelin sheath, the outer white insulating sheet surrounding nerve fibres. Think of myelin as the plastic coating on electrical wires. If there is reduced myelin, signals cannot travel normally from the brain through the nerve cells. My graduate thesis involved de-myelination in the proband that lead to a Wernkie's-Korsakoff presentation in an 18 month old child. Mild loss of myelin can result in reduced brain function, nerve problems and confusion. The worst part is, once the myelin is destroyed, no amount of fat is going to replace it. So it is very, very important to not restrict dietary fat to the point of causing a deficiency. The second factor in restricting dietary fat comes from the fact that fat makes fat. In reality, fat comes from starch that was converted from sugars (carbohydrates). If the body cannot use the sugars ingested, it converts them to starch which is then converted to fat, likely part of our evolutionary make-up to provide nourishment from within when food was sparse.
Fat add flavour, flavour, flavour! At the same time it makes the meat tender and juicy. While some trim the excess fat from steaks, we do not trim if grilling. Excess fat can cause flare-ups on the grill but flare-ups can be easily controlled. The outer fat drips down into the grill adding to the smoke flavour. Fat is easily cut off before eating the steak. The inner fat (marbling) reduces when grilling while keeping the meat moist and juicy.