Outbound I had ZERO issues. I had 5 full MRE meals in my carry on. These MREs included the self-heater. I think TSA was supposed to inspect them to verify they were unopened, but they did not (unless they can somehow tell that from the xray?). This particular airport has a lot of military personnel come through, so the TSA was likely familiar with the item there.

On the return I had a couple left over MREs (ended up cooking some steak over the campfire ); I again had no issues. However, the xray screener did run my bag through a second time, but that was it. No manual inspection or anything.

I had a lot of other camping gear in my carry on, so perhaps that cued the screener to what it was. Or perhaps I just got lucky. I don't know, but based on this one occurrence I must say I was a bit impressed, because I was fully expecting to have them thrown out.

One thing, though... both airports are very small... around 10 gates. It would be interesting to see if the TSA at a larger airport is as familiar with some of the more obscure rules like this.