This is an older article, so I'm not sure all the links are still good

Napoleon is credited with saying, "An army travels on its stomach. Soup makes the soldier." Army rations http://www.qmfound.com/history_of_rations.htm in Napoleon's day consisted often of bread and soup, http://home.vicnet.net.au/~oz21eme/Sac.htm supplemented with wine and vinegar, as an antiscorbutic to prevent scurvy. http://www.who.int/nut/documents/scurvy_in_emergencies_eng.pdf . Napoleon is also credited with encouraging the idea of preserving foods by canning. http://www.cancentral.com/history.htm All of this comes under logistics, http://www.almc.army.mil/alog/issues/JanFeb01/MS585.htm a major expense of campaigning. http://www.napoleon-series.org/research/abstract/military/army/france/logistics/c_logcosts.html

100 lbs of flour will produce 130 lbs of bread; in making biscuit, 100 lbs of flour will only produce 90 lbs of biscuit. Not only is the water used in preparing the dough evaporated, but the water in the flour (which comprises 10% of its weight) will also be lost. Biscuit is made of wheat meal with only the coarsest bran removed. It consists of flour and water with no salt or yeast. Good biscuit should be pale fawn in color with a smooth, even appearance. Inside it should be golden white. It should be perfectly dry, with a "clinky" sound and make an even break. (p. 284-5) Biscuit takes 3 times as long to bake as bread. (p. 289)

A field oven of brick 9 feet 3 inches long, 7 feet wide and 20 inches high requires 5 stove setters and 8 laborers to prepare. It requires 4 hours to build and more than 6 hours to dry. It will require 2 hours to heat before each baking and each baking (for bread) requires 2 1/2 hours to yield 432 lbs of bread. At most 5 bakings are possible in 24 hrs.
--Furse. Organization and Administration of the Lines of Communication in War. (1894)

"Meat cooked overnight and carried in a haversack is not palatable; it soon gets bad, and cannot be considered sufficiently nourishing for men performing hard work….Meat coming from requisitioned animals killed on the spot is neither good to eat or good for the health; it has not a good flavour, and takes too long to cook. In any case, meat, if possible, should not be eaten for twenty-four hours after it has been killed. If killed in the evening, and carried in the regimental carts [Furse says it should be given air-- laid on straw and protected with a tarpaulin], it will be good the next day. It is preferable to carry it in quarters than to cut it up to be carried by the soldier, for, in the latter case, in 24 hours it is no longer eatable."
--Furse. Organization and Administration of the Lines of Communication in War. (1894)

Marshal Marmont, "De l'Esprit des Institutions Militaires."(1845), in: Furse, Organization and Administration of the Line of Communication in War. (1894)
(p. 293-296)

"On the subject of the soldier's food, I shall only speak of the provision of bread; that alone presents some difficulties, the supply of cattle for slaughter being always more within reach of the consumers.

"The difficulty in securing a regular distribution of bread is one of the greatest embarrassments in war. It is inexplicable how so many distinguished generals, who, on this account, have been crossed or hampered in the execution of their plans, have not arrived at a solution of such an important problem.

"The Romans had solved it; but in general their wars did not require such rapid movements as are needed in modern warfare.

"There is, I believe, a perfectly satisfactory manner to contend with this difficulty, and the alteration which I propose will have a powerful influence on the art of war.

"To receive regular distributions of bread by means of the administrative service, it is necessary for an army to be stationary or in retreat, remaining always the same distance from the magazines or drawing closer to them; if it advances, it gets in a constant manner further and further away from them, and the operation becomes impracticable for a commissary, however able he may be; because the convoys cannot proceed faster than the army, and must follow it at the same relative distance they were at the moment of departure; at each following despatch of a convoy, the distance increases, and the difficulty becomes greater.

"In a war of invasion the troops can only live on the resources of the country they traverse. But the time required to manufacture the bread in inhabited localities, the ordinary insufficiency of mills and ovens, or their distance, render the local resources very incomplete; and the want which results causes great sufferings and serious disorders. Still, on the maintenance of order under every respect and by all means depends the safety of armies.

"The only certain way of insuring the regular subsistence of the soldier, is to impose on him the duty of looking after it himself, in accordance with some arranged plan. I have tried this, and the result has been entirely favourable.

"War is not carried out in a desert, and when this exceptional circumstance arrives special dispositions are taken to meet it. War is generally made in inhabited countries, and where there are men there is grain to feed them with. It is in the manner of utilizing the grain which the granaries contain that the solution of the question really rests.

"The main difficulty, as I shall explain further on, is to reduce the corn into flour. Therefore mills to grind the corn are needed; it is possible to exist, if need be, only on flour without turning it into bread; but one would simply die of starvation on a few handfuls of grain.

"When labour is scarce and rare there is an advantage in employing powerful machines in the manufactories and in centralizing work; but when labour is superabundant and costs nothing it is better to follow an entirely opposite system. In relegating the works from the centre on to the circumstance they are rendered far easier; and in confiding them to those who have to profit by them, their zeal and their punctuality are insured. This being granted, it is evident that we can utilize the manual labour of the soldiers without any inconvenience, and that it is an advantage for them to receive as an indemnity the price which the extra work with which they are burdened costs.

"Why is it that in the field the soldiers never run short of soup, when they have meat, bread, and camp-kettles? It is because they prepare it themselves. If, under any pretext whatever, a commissary had imagined to provide it for an entire division, or even a colonel for his regiment, in moving about, the soldier would never partake of it.

"I desire to apply to the bread the same rule as applies to the soup, and the soldiers will never be in want of it. I propose to give to the army portable mills; I adopted this measure in one of the Spanish campaigns, and it answered thoroughly. The army of Portugal, in 1812, existed thus during six months; the only inconvenience that was found was that the millstones got very soon out of order; this was remedied by the means of better tempering, and very lasting ones were made.

"Napoleon, in the midst of the miseries of the Russian campaign, having heard of these results, was struck with the advantages which might be derived from them; and he ordered a large number of these mills to be made for the Grande Armée. Five hundred were sent to him, which arrived at Smolensk when the army was returning from Moscow. But already there were no longer any arms to move them or men to make use of them.

"These mills should fulfil the following requirements:—'First, to be as light as possible, capable of being carried by a soldier, who, looking at the importance of the subject, should be detailed from the ranks for the purpose, when the regular means of transport fail; second, to be capable of being worked by a single man; third, to yield fine flour, and sufficient in four hours' work for the needs of a company.

"The mills of the army of Portugal gave thirty pounds of good flour per hour. It has been objected against this system that, the regulations having prescribed the extraction of the bran, this operation complicated the manufacture. I reply that the experiments made with grain of good quality have demonstrated the uselessness of extracting the bran.

"Even with grain of middling quality, but pure and unmixed, the bread is always good. When supply officers issue bad bread, the soldier must necessarily take it and eat it, or he must die of hunger, because the time for its consumption admits of no delay; but when the grain which is issued to him is full of dust or of whatever other mixture, it is possible to clean it before using it, and the soldier will then always eat good bread. Therefore, also under this head, his condition will be improved; it will be further bettered by the indemnity which he will receive for his labour either in money or in an increased ration.

"Look, on the other hand, at what will be the gain on the part of the administrative officers, the habitual simplification, and in time of war the expedition of their work. A general in command now exerts his mind more to secure the subsistence of his troops than anything else, and his combinations are unnecessarily defeated for want of a timely distribution of bread.

"Not only the question of the indispensable nourishment allotted to the troops, but also that which regards the bread ration properly so called, has been thus solved. The way of constructing ovens by a simple excavation in any kind of soil in four hours, and which two hours after can serve to bake bread in, has been found. Thus in every bivouac, flour is ground in sufficient quantity for the daily consumption; and at each halt or period of rest ovens are made in the ground in suitable localities in which bread is baked in advance. From this moment the supply of the army progresses by itself; the administration is no longer troubled by these details, any more than each man is in insuring the circulation of his own blood; it is the result of a principle which operated steadily.

"In peace-time, the Government will maintain stores of grain from which issues will be made to the troops. It will be the same in a defensive war. In a war of invasion, each regiment will receive daily from the administrative officers of the country traversed, or will seize in the granaries of the population, the grain of which it is in need. However, it is essential for this to be a custom followed and contracted in time of peace; because, as a rule, the usages of peace should be assimilated as closely as possible to those of war; this truth is incontestable when it is a question of introducing a great alteration."

`A View of the French Campaign in Russia in 1812`, by `an officer, Swansea, 1813.
`Suppose an army consists of 300,000 infantry, 50,000 cavalry, 50,000 Followers; total 400,000.
Bread - each man will require 1/2 lb of bread per day; 4,200,000lbs each week.
Meat - Beef or mutton. Each man would require 1/2 lb per day. A bullock gives about 500 lbs; each sheep 50 lbs. Each week it would require 1,400 bullocks and 14,000 sheep. Or 1,400,000lbs.
Drink - 1/2 pint of wine or spirits per day; 1,400,000 lbs per week.
Horses for the cavalry, staff, regimental baggage, ammunition and commissariat - ca. 150,000 horses.
Oats - each horse would require per day 8 lbs; making per week 8,400,000 lbs.
Hay - each horse would require 12 lbs; making per week 12,600,000 lbs.
Now all this requires carriage. Suppose the magazines 50 miles in the rear, and that each horse goes 100 miles per week; it would require, for the transport of only the food for this army 112,000 horses.
This number also must be fed, thus needing a further 4,659 horses to carry their food and food for themselves.
Oats for these per week at 8 lb per day for each horse is 6,532904 lbs and hay at 12 lb per day for each horse is 9,799,356 lbs per week, making in the whole, 44,332, 264 lbs or 22,180 tons.`

"It was left to Napoleon's genius to find a mean between the old system of magazines and the system of requisitions; he accepted what there was good in both, and made them harmonize. His rapid movements would have been impossible had he strictly adhered to the system of feeding his armies from magazine.... he turned his attention to a more systematic way for providing for the alimentation of his armies; he established magazines at the base of operations, and requisitioned locally, either to fill his intermediate magazines or to provide for the immediate wants of his troops.... [He] employed a large train to bring up, either from the primary base or from the intermediate ones, such provisions and stores as the enemy's territory could not furnish." P. 197-8

"Napoleon's continuous progress in his first Italian campaign, and his rapid advance on the Saal, in 1806, would have been impossible had his troops been bound to rely for their subsistence on convoys bringing up food from the rear.... Napoleon owed much of his success on the masterly way in which he concentrated very large masses of troops, at the right time, for battle. Fully impressed, however, with the enormous difficulties which attend the feeding of large masses of men and animals in a restricted area, he only gathered them together when action was imminent. He indicated by this practice the general principle of spreading the several army corps or divisions so as to facilitate their alimentation, but to do this so prudently as to experience no difficulty in gathering them together when required." P. 202

Col. George Armand Furse. The Organization and Administration of the lones of Communications in War... 1894.