The Oils and Fats consist of the same elements as the carbohydrates, but the hydrogen is in larger quantity than is necessary to form water, and this surplus is available for the production of energy.  During their combustion in the body they produce nearly two-and-a-quarter times (4 :  8.9 = 2.225) as much heat as the carbohydrates; but if eaten in more than small quantities, they are not easily digested, a portion passing away by the intestines.  The fat in the body is not solely dependent upon the quantity consumed as food, as an animal may become quite fat on food containing none.  A moderate quantity favours digestion and the bodily health.  In cold weather more should be taken.  In the Arctic regions the Esquimaux consume enormous quantities.  Nuts are generally rich in oil.  Oatmeal contains more than any of the other cereals (27 analyses gave from 8 to 12.3 per cent.)

The most esteemed and dearest oil is Almond.  What is called Peach-kernel oil (Oleum Amygdalae Persicae), but which in commerce includes the oil obtained from plum and apricot stones, is almost as tasteless and useful, whilst it is considerably cheaper.  It is a very agreeable and useful food.  It is often added to, as an adulterant, or substituted for the true Almond oil.  The best qualities of Olive oil are much esteemed, though they are not as agreeable to English taste as the oil previously mentioned.  The best qualities are termed Virgin, Extra Sublime and Sublime.  Any that has been exposed for more than a short time to the light and heat of a shop window should be rejected, as the flavour is affected.  It should be kept in a cool place.  Not only does it vary much in freedom from acid and rancidity, but is frequently adulterated.  Two other cheaper oils deserve mention.  The “cold-drawn” Arachis oil (pea-nut or earth-nut oil) has a pleasant flavour, resembling that of kidney beans.  The “cold-drawn” Sesame oil has an agreeable taste, and is considered equal to Olive oil for edible purposes.  The best qualities are rather difficult to obtain; those usually sold being much inferior to Peach-kernel and Olive oils.  Cotton-seed oil is the cheapest of the edible ones.  Salad oil, not sold under any descriptive name, is usually refined Cotton-seed oil, with perhaps a little Olive oil to impart a richer flavour.

The solid fats sold as butter and lard substitutes, consist of deodorised cocoanut oil, and they are excellent for cooking purposes.  It is claimed that biscuits, &c., made from them may be kept for a much longer period, without showing any trace of rancidity, than if butter or lard had been used.  They are also to be had agreeably flavoured by admixture with almond, walnut, &c., “cream.”

The better quality oils are quite as wholesome as the best fresh butter, and better than most butter as sold.  Bread can be dipped into the oil, or a little solid vegetable fat spread on it.  The author prefers to pour a little Peach-kernel oil upon some ground walnut kernels (or other ground nuts in themselves rich in oil), mix with a knife to a suitable consistency and spread upon the bread.  Pine-kernels are very oily, and can be used in pastry in the place of butter or lard.