Without going too far down the rabbit hole, a few run downs:

-While Washington's soldiers at Valley Forge definitely ate firecake the first few weeks of the encampment, once the 20+ bake ovens and the baker general showed up early January, soldiers were getting 1-2lbs bread pretty much daily. They weren't getting full rations by any stretch (1lb flesh, 1lb bread, grains, vegetables, and rum ration). They were hungry. They were burning more calories than they were consuming. Soldiers were debating mutiny due to lack of meat. But they weren't quite at the point of starving. It's bad, soldier's lack of nutrition is not helping the near epidemic disease issues in camp. They are gaunt and hungry and lean and not getting everything they need. Things generally get almost to the breaking point of lack of food, but then a herd of cattle come into camp and things are placated.

The bad starving year is Morristown, two years later, where they eat officer's dogs. Things improve once the commissary is centralized and revamped by march and more and more equitable distribution of food starts. There's a good table of food coming into camp in Figure 1, between page 126 and 127 of the Valley Forge Report (https://www.nps.gov/vafo/learn/historyculture/upload/Vol-2.pdf)

-In the archeology and written record of the encampment, there are no horses killed for meat. Washington has to instruct the soldiers that they need to bury the dead horses (not enough hay) because they are rotting and causing disease. This is at the end of February. Soldiers that are starving will eat a dead horse. They don't. (Washington's daily commands to camp, late February 1778)

-Rations for commissioned officers are kind of across the board, since they were frequently responsible for finding their own lodgings, paying for them, and procuring their own equipment. It's markedly different from current military. There are public markets with product available (pg 185/186). We believe that Martha Washington had some sort of 'cake' made for George's birthday, although it would be more similar to a fruit cake than cakecake. Based on archeology from trash pits behind Washington's Headquarters, we know that he ate a LARGE number of oysters, generally gifts from various southern-y states and folks. We also know there was a lot of pork. It’s hard to know individual qualities, how much each person was getting because there were anywhere between 15-20 people in headquarters at any given time. So rations were better for the commanders—more meat, greater likelihood of fresh vegetables, much greater likelihood of alcohol mostly due to the ability to purchase these items with their own funds. But they weren’t immune to the supply issues.(https://www.nps.gov/Archeology/sites/npSites/valleyForge.htm)

Sorry to have to run from this and not spend more time with the Valley Forge Report, but all the info you need would be in there.