This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
Chocolate is manufactured from the husked, dried, ground, and fermented cocoa seeds, which are then roasted and made into paste and compressed into cakes by moderate pressure. To increase the flavour and nutrient power of the cakes more or less sugar (but at least 50 per cent) is added, and various flavouring extracts, such as vanilla, etc., or spices, are mixed with the paste before compressing it. The husks of the seeds are separately sold, and are used for adulteration in making cheaper varieties of chocolate. They are inferior to the seeds in all their properties.
The value of chocolate as a concentrated food is in part derived from the sugar which is added, but it is very nutritious. Tested at the Austrian army manoeuvres in 1900, a chocolate ration was found to equal five times its weight of beef. Like cocoa, if pure and carefully prepared, its ingredients are easily digested and absorbed. In cases of dyspepsia and various gastric disorders it forms an agreeable and wholesome drink, and it enables the patient to take additional nourishment in the form of the milk and sugar mixed with it. It is also mildly stimulating and exhilarating to the nervous system when exhausted through overwork or worry, and it possesses the advantage over tea and coffee that it does not produce wakefulness. The free use of chocolate, either eaten or drunk as a beverage, constituting what almost might be called a "chocolate habit," is not injurious to the nervous system after the manner of overindulgence in tea and coffee, but it produces more or less gastric dyspepsia on account of the large quantity of sugar which it already contains or which is added to it when drunk.
Chocolate made into compressed cakes forms a convenient portable food that will keep well for a long time, especially when protected from drying by a coating of tinfoil or otherwise. These cakes contain condensed nutriment which makes them very serviceable upon expeditions where provisions can only be carried in limited quantity. Condensed milk may be carried to drink with the chocolate. The fact that its flavour is so universally liked is an additional advantage.
The chocolate cakes are sometimes prepared with meat extract, or when dissolved and drunk, meat powder or raw meat may be added to them for phthisical patients or other invalids who require concentrated food.
Chocolate, when not too rich in fat, is a very wholesome food for growing children, and is better for them than the more stimulating beverages tea and coffee. Its agreeable flavour causes it to be extensively used as an ingredient of starchy foods and confections, and also to disguise the taste of disagreeable or bitter medicines, such as quinine. Many articles of invalid diet, such as cornstarch, farina, gelatin, etc., may be made palatable by the addition of chocolate, while their nutritive qualities are enhanced.