Beef fat, especially grass fed, is great. Chicken or pork fat varies from great to bad according to what the animal is fed. If they're fed soybeans, which they typically are, the fat is high linoleic and is bad. So not all animal fat is the same. (Cattle can be fed soy but the fat still is low linoleic due to their different digestive system.) Not all plant oils are evil. Macadamia oil is healthy. So are coconut oil and olive oil. All these are low linoleic. Avocado is moderate in linoleic acid so if the rest of your intake is low, moderate avocado oil is fine. It's not that linoleic acid would optimally be zero, in fact getting some is required, but problems progressively appear as the percent in diet exceeds about 10% of the fat consumed.