Fats And Oils
THE main purpose of this book is not merely to provide a guide to good nutrition at a low total fat level; almost equally important is the proper selection of the fats you eat. We have paid careful attention to this in the menus and recipes offered.
If you only want practical advice without worrying about the reasons involved, it may be enough to observe the following points: All food fats and oils have about the same calorie value, but they differ in their effects on the blood and, probably, on the tendency to promote deposits in the coronary arteries. The fats that are most liquid at ordinary temperatures are usually most acceptable in this respect. These are generally "unsaturated" fats. The hard fats, whether of animal or vegetable origin, are the ones to be most carefully restricted. These are the "saturated" fats.
Among the fats to be favoured are cottonseed oil, corn oil, sunflower seed oil, safflower seed oil, sesame oil, and the fats in fish and shellfish. Most, but not all, natural fats of vegetable origin are in this class.
Among the fats to be used with discretion in the diet are dairy fats (in butter, milk, cheese, etc.), beef, pork, and lamb fats, lard, coconut oil, margarines, cooking fat, and the fat in chocolate.
In an intermediate position are olive oil and peanut oil and, rather less desirable, egg and poultry fat. The oils in nuts range from "intermediate" to "good" in respect to the effect on the blood cholesterol.
Large amounts of fats of any kind in the diet are to be avoided because of their high calorie density - far more calories per mouthful than you get in any other kind of food. Also important may be the avoidance of a large amount of fat in any one meal because this may change the clotting property of the blood for some hours after the meal. As yet there is no proof that this explains why so many fatal thromboses occur four to eight hours after a large fatty meal, but why not play safe?
Special oil preparations in fancy packages, for use in salads and cooking or to be taken before or with meals, are being promoted for "protection against heart and artery disease". None of these is recommended as being more desirable than the common corn and cottonseed oils available at far lower cost at every grocer's shop.
Trade names of oils and oil preparations containing the syllable "saff" generally refer to safflower seed oil. This is a highly unsaturated oil containing lots of the "essential" fatty acid, linoleic acid, but it is not significantly different in effect on blood cholesterol from more common vegetable oils such as corn oil. Among various cooking oils now available on the British market, "Jessamine" is cottonseed oil, "Mazola" is corn oil, "Twirl" consists of a mixture of cottonseed and groundnut oils, and "Saladin", "Wesson 44" and "MacFisheries Superfine Oil" are groundnut oil. Besides these, pint and gallon cans of sunflower seed oil and corn oil can be obtained from vegetarian and "health-food" shops without much difficulty.
Read the labels on the food products you buy. "Hydrogenated" or "Improved by Hydrogenation" simply means that the natural oil has been treated to make it less liquid, thereby destroying most of the essential fatty acid and converting the oil to a more saturated fat which is less desirable in regard to blood cholesterol than the natural material.
The idea that only butter or lard can be used for some types of cooking is a myth from the days before refined oils other than olive oil were widely available. But one-to-one substitution does not work, and cooking times and processes require adjustment. Our recipes are thus adjusted and other recipes are to be had from the companies selling oils.
It is not true that heating oils, as in ordinary cooking, or a reasonable re-use of frying oils, makes them dangerous. But never use a rancid or off-flavour fat or oil. Your nose is more sensitive than most chemical tests.
Special margarines containing more linoleic and less saturated fatty acid than the usual type have been developed recently, and these may soon become available on the British market. Such a margarine should have considerably less cholesterol-promoting effect than either ordinary margarines or butter.
The substitution of a fat of this type for the far more saturated fats ordinarily used for the same purpose undoubtedly would tend to reduce the serum cholesterol level in the blood. But the would-be purchaser should examine the labels of all margarines offered to control blood cholesterol to make sure the product is, in fact, unusually low in saturated and high in poly-unsaturated fats.