First, determine what are such recommendations. Are they generally order our food to be useful. In this case, the frying of the question should not be, in principle. Because, what would have been oil, at high temperatures it emits harmful substances. And difference properties of oils during frying, whether refined or unrefined, is unimportant.
After frying formed transfats. This, in turn, leads to blockage of blood vessels, atherosclerosis. Atherosclerosis is not the only threat to the ingestion of food after frying. You may also experience Alzheimer's disease, Parkinson's disease and cancer.
Most Housewives are at home does not use oil again. But when talking about production on an industrial scale or catering establishments, the situation is quite different. In this case, the products are processed in oil, which is used repeatedly, turn toxic and very harmful to health.
The difference between homemade food and products catering significant. But in any case, the food subjected to frying process, is not healthy. If we are talking about the process when the food forms a ruddy, Golden, it is undoubtedly a high temperature. When the oil escalivada to such a high marks, the formation of mutagens that affect DNA cells.
Quite another matter if we speak about such ways of cooking like stewing, vexation, or steaming with butter in it. Because at low temperature, to one hundred and fifty degrees, useful acids contained in the oil are not broken down and the carcinogens are not formed. If the temperature is higher, harmful substances are emitted. And no matter what kind of oil to use.