Horrror about woman who keeps eating then Kills her mother

The movie you are looking for is Criminally Insane (1975). It is a true gore grindhouse cult classic. I bought an empty VHS case of this movie thirty-some years ago just because the cover art was so freaking fantastic. It took me years to finally track down a copy of the tape so I could see the movie. For once, the movie actually lived up to the great cover art.

Poor Fat Ethel. She has just been released from an insane asylum into the care of her grandma. Grandma is determined to get Ethel on a diet and nags her endlessly. But Ethel doesn’t take to carrots and celery sticks. In desperation, granny locks the pantry, which sends Ethel over the edge. Fat Ethel hacks granny with a butcher knife to get the key, scarfs down a few thousand calories of cookies to replenish her energy after all that exertion, then drags granny’s body to the bedroom and locks the door. Next to die is the poor grocery delivery boy when Ethel can’t come up with enough money to pay the bill. The kid joins decomposing granny in the bedroom. Next, Ethel’s annoying sister Rosalie shows up and announces she’ll be staying a few days, and where the heck is grandma anyway? Rosalie and her boyfriend get a little too snoopy and Fat Ethel has just the right meat cleaver to solve that problem. You don’t want to get between Ethel and her next meal.

Director Nick Millard worked under a lot of different names, mostly directing porn. Criminally Insane was his attempt to branch out into mainstream films. He made a direct to video sequel in the 1980’s, but I’ve never seen it. There is a great copy of the full movie on youtube if you want to confirm this is the correct movie.