Degeneration of the Human Diet - a Brief Timeline:

- Paleolithic era began around 2.5 or 2.6 million years ago 
- Neolithic era (first agricultural revolution; marked increase in grain
consumption in fertile river valley areas in what is now Egypt, Iraq, Israel
and China) began around 9-16 thousand years ago
- First widespread "fast food" (if we don't count beef jerky or pemmican):
perhaps the rations of the earliest imperial armies, such as the Egyptian
and Persian imperial armies (grain gruel) and the Roman imperial army
(bucellatum--a hard bread cake akin to "hardtack" with a long "shelf
life"--and puls--a grain gruel). Dysentery and scurvy were likely major
problems for these armies. Around 3,000 BCE to 0 CE these armies spread the
pernicious practice of eating grain as a staple food across much of the Near
East, North Africa and Europe, slaughtering or enslaving those who refused
to submit to a system of totalitarian grain agriculture and labeling
hunter-gatherers and pastoralists as "barbarians." 
- Second agricultural revolution occurred around 1700 - 1900 (marked
increase in grain consumption across most of the world)
- Industrial revolution: around 1740-1900
- Modern food processing: began after 1800, mainly at first to supply
European armies
- US Civil War: prompted the development of factory-produced "hardtack" and
was accompanied by large-scale dysentery and scurvy, with Colonel Custer
later calling scurvy the biggest problem he faced during his cavalry's
pacification of Plains Indians
- WWI, WWII and the post-war American and European baby boom accelerated
food processing
- First drive-through fast food restaurant: 1948 (In-n-Out Burger)

Notice how large-scale wars accelerate the development of modern foods, as a
result of the need to feed massive armies across fairly large distances?
Ironically, the agrarian societies which produced the first massive armies
and systems of serfdom are currently regarded as the greatest human
achievements up to that time. Along with forced agrarianism, these
"civilized" societies spread epidemics of chronic and infectious disease,
which further weakened and decimated their "barbaric" enemies. It will take
a major cultural shift for societies to realize that the hunter-gatherer and
pastoral ways of life were largely superior (though not without their own
problems) to that of the later "civilized," grain-based societies, and
better suited to long-term survival of the human species.

The US Civil War in particular did much to accelerate the transition to
industrial food processing and illustrated some of the horrors that can
result. A typical camp meal of Union soldiers was pork (sometimes fresh from
plundered hogs), soft bread or hardtack, rice and/or beans, and coffee with
sugar. Fresh vegetables and dried fruits were only issued occasionally as a
scurvy preventative rather than as staple foods. The benefits of fresh and
raw meats and organs were not even understood. Union officers got more fresh
meat, fruits and vegetables, so they tended not to suffer any dysentery or
scurvy. A typical infantry marching ration was worse than the camp rations:
hardtack, salt pork and coffee with sugar--a recipe for the dysentery and
scurvy that plagued the Union army. 

Dysentery and scurvy were even worse problems among the Southern army. A
notable exception to this was those American Indian irregular troops who
lived off the land and what they plundered--most famously Stand Watie's
cavalry on the Southern side. Watie's troopers were not reported to suffer
from any dysentery or scurvy and had what they considered the best rations
in the entire Southern army--probably either army--with fresh meat nearly
every day. Waitie's was the most successful command on the Southern side and
his troops were the last to surrender, proving once again that fresh meat is
prime warrior food.

Hardtack, like any refined carbohydrate food, was not filling. Instead, it
tormented the men by making them more hungry. Yet the soldiers mistakenly
continued to think of it as "nutritious food." As one soldier put it, "While
hardtack was nutritious, yet a hungry man could eat his [ration of] ten in a
short time and still be hungry." Hardtack was prone to become rock-hard, wet
and moldy, or infested with weevils and maggots. Usually the hardtack was
crumbled into coffee to make the "flour tile" more palatable, often leaving
stranded weevils swimming at the surface. The soldiers skimmed the weevils
off, which was unfortunate given that they were far more nutritious than the
hardtack.