However, there are two types of fats that are harmful to us - because thay form deposits in tissues and organs causing degeneration and diseases.
Similarly to resins and fruit esters - polyunsaturated oils also called drying oils - accumulate and dry up in nerve tissue causing hormonal, immunological and cognitive deficiencies.
Drying fats (i.a. linseed oil, hemp oil, polyunsaturated fractions of edible oils) cross-link (dry up) spontaneously or much more quickly when come into contact with lactic acid naturally found in tissues.
Drying oils have been used for centuries for oil paints production - but they are not suitable for the lubrication of machines (they form sinters) and are not edible as well.
The other type of harmful fats are hard (long-chain) fats which in body temperature are solid. Tallow and other hard fats from nuts are gradually deposited in tissues causing their degeneration. Contrary to false opinions promoted in the media, nuts are not healthy - the contain both drying and hard fats.
Good fats are saturated fats that are liquid at body temperature, i.e. butter, chicken/goose fat, olive oil from mature (mature=saturated) olives, refined sunflower oil. The common problem with olive oil is its falsification! Canola oil is a marketing name for rapeseed oil which contains some harmful erucic acid.
How to check if the sunflower oil or olive oil does not contain a polyunsaturated drying fraction? Lubricate the plate with it and leave in the sun - ultraviolet accelerates drying reaction. If after a few days the oil thickens, it means that it is inedible. Easy scorching of the oil when frying is also a clear symptom that oil contains polyunsaturated fraction and is inedible.
The butter contains high-order alcohols, which have the properties of dissolving some fruit polyesters. Butter must not be heated to keep the property as the alcohols evaporate when heated.
