www.alphadictionary.com

Some of the Agora may be interested in this idiom. With my vegetable garden at its peak, my dear wife Facebooked (I don't Facebook) that "We are living high on the hog." She got some quizzical responses and had to explain. The idiom means, of course, "We are living comfortably or even we are very well off." The explanation is in the cuts of pork one can afford. High on the hog are pork chops, Canadian Bacon (regular bacon in England), pork loin, gammon steaks (for the English), cured hams, etc. Not so high on the hog are American bacon, sowbelly and pork sausage made from scraps. Low on the hog are sweetbread (the pancreas), chitlins (intestines), lights (lungs) and, lowest of all, pickled pig's feet.

I hope I have whetted your appetite.

Here's a nice write-up on the theme.

According to a webpage I found, the oldest citation for the phrase in the OED is
"from the Nov. 28, 1919, issue of the Kansas City Times: ' "Dese days I’se eatin’ furder up on de hog!" "We’re all eating too high up on the hog," Mr. Clyne concluded.'"
The Ngram tool shows usage of the phrase starting to increase in the 1930's. It doesn't look like it was used at all prior to that. (The only example I found is the one above, and I didn't find it myself.)