Casomorphins are protein fragments from the digestion of Casein—milk protein. Casomorphins have an opioid effect—resulting in addiction to cheese. Sep 19, "I did a bit of a search and I found a study that lead to this discussion around whether cheese is addictive or not, and I found it quite interesting. Oct 28, Headlines arguing cheese is as addictive as cocaine have it wrong. Freaky Eaters Oct 28, Headlines arguing cheese is as addictive as cocaine have it wrong. Oct 22, For years you've been telling your friends, family, co-workers and anyone who will listen that you're addicted to cheese. It's a part of every meal. Mar 7, Cheese is addictive, according to author Dr. Neal Barnard, because the dairy proteins inside can act as mild opiates.