Ralston Purina used to own Jack-In-the-Box. 
Loaf, according to at least one correctional facility.
I am so making some of that Loaf this weekend. I’ll report back on how it was.
Oh lord that is terrible. I managed about one slice before I couldn’t do it any more. No one under any circumstances make that stuff. I’m going to have to throw the rest away.
Well, there is One Square Meal .   One “outer” (two of the green wrapped bars) is [sup]1[/sup]/[sub]3[/sub] of the  RDI of the average person.  Of course there is the usual disclaimer about a varied diet.  As there is only one flavour (apricot) I think I’d not to be able to live by them alone, plus the cost of about US$3 per meal.  I carry a couple in my kit so if I’m going to miss a meal there’s no need to panic. 
They work, I feel full and have normal energy levels shortly after feeding. 
Dave