Have tried an MRE or two. Meh.
Our commissary (military grocery store) sells Tailored Operational Training Meals (TOTMs) singly or by the case. TOTMs are much like an MRE, with a few things removed. About 1000 calories vice MRE's 1200-1300. Sell here for $50-55 for case of 12, depending on the manufacturer. MRE's would go for twice as much.
Have eaten one or two TOTMs. Okay, but not for the long-term. Have a couple at home, for whatever.
According to the Army Surgeon General, MREs are supposed to be used for 21 days or less as the primary meal in the field. Fresh/Ultra High Temperature packaged milk (supplement), fresh fruits/vegetables, and fresh bread (enhancements) should also be supplied as soon as possible, as often as possible. First Strike Rations (basically snack foods compactly packed) are to be the primary means of feeding for no more than three days.
The Marines' standard field feeding plan is two hot meals (normally breakfast and dinner) plus one MRE for lunch. The Army's standard field feeding plan is three quality meals daily. They have a wider variety of field rations available to them than the Marines. An interesting note - supplying rations/food to Marines in an active operational area after the 90-day mark is usually an Army mission. The Army has more logistical assets available than do the Marines.
Military rations and military field feeding are very interesting subjects. A little powerlevel - this is a hobby of mine.
An army marches on its' stomach. You can do a search and find a lot of material. Good website - MREinfo.com. They deal with US contemporary rations (MREs/First Strike Ration/MCW/MORE), as well as historical rations, such as the C-ration. International rations are also covered. Good forums on both US and foreign rations. Discuss, review, buy, sell, etc.
If you are even thinking about ordering foreign military rations containing meat on eBay, especially Russian rations, to be sent to the USA, be aware that the USDA prohibits the importation of the vast majority of canned meat in these rations. They can and do open up these rations in the mail and remove the offending item(s). They can also file complaints against you. Big thread about it in the foreign ration forum. Some guy had a lot of dealings with the USDA about this. He turned in the offending canned meat and they finally left him alone.
If interested in German WWII rations and field feeding, Jim Pool has put out an outstanding book, in two volumes,
Rations of the German Wehrmacht in World War II. Available on Amazon, new and used. May as well buy them new - these books are definitely keepers.
The US Army also has a very extensive ration and field feeding program, first went into top gear during WWII, and has proceeded onward ever since. Check out the Army's "Green Books" on the Quartermaster Corps, including separate volumes for QM Corps activities against the Germans and the Japanese. These books are all downloadable free of charge. Go to history.army.mil. Then click on the time saying U.S Army In World War II. You go to a list. Click on "The Technical Services". From there, you go to Quartermaster Corps.
These days, the Army does their ration research and development at their Natick Soldier Systems Center. Once a ration has been developed, standardized, tested, and ready for issue, units get the rations from the Defense Logistics Agency. Huge operation. DLA provides more than just field rations. They are the primary source for food eaten in military dining facilities, of all services, worldwide. They have contracts out the ass with various vetted providers to service US bases overseas. You can't believe how big a business this is. The military needs to eat their three meals daily. Takes a lot of food -the right types, in the right places, at the right times. If interested, go to
https://www.dla.mil/TroopSupport.aspx. From there, click on "What Troop Support Offers", then click on "Subsistence".
As a side note, DLA has partnered with the US Agriculture Department to provide fresh fruits and vegetables for school meal programs in 47 states.