Philon of Byzantium developed a ration pill for his soldiers in 150 BC. This pill was the size of an olive and was made of sesame seeds, honey, opium, poppy seeds, and squill (which is a root plant I've never heard of).
The pills were made to provide protein (from the sesame seeds), hydrocarbons (the honey), helped a person be free of pain from hunger and/or discomfort (opium), and a general tonic (the squill).
Active soldiers got two pills a day, one at 8 am, and the other at 4 pm. They also drank vinegar on a regular basis.
So, now you know!