Patent No. 4,344,424: Anti-Eating Face Mask was awarded to Lucy L. Barmby of Sacramento, CA in 1980. What surprises me is not that this apparatus was granted a patent but rather than even 34 years ago self-restraint in terms of food was a problematic issue. "An anti-eating face mask which includes a cup-shapes member conforming to the shape of the mouth and chin area of the user, together with a hoop member and straps detachably engageable with a user's head for mounting the cup-shaped member in overlying relationship with the user's mouth and chin area under the nose thereby preventing the ingestion of food by the user."
If you squinted really hard and took a couple grains of salt, I'm sure you can see that this apparatus is actually much needed and useful to all those who need a physical restraint from "introducing substances into the mouth" which could include objects greater than food. In the matters of non-obviousness, I would consider myself a person of ordinary skill well cultured with putting objects into my mouth (for about 20+ years now) and would definitely not have thought of such a intricate device to disable one from introducing objects into the mouth. As for novelty, no prior art seems to exist with such an innovative apparatus in any country or publication. Thus this patent is valid enough to be granted as a patent.
Weight Loss companies may want to look to gain a licensing agreement perhaps..