As I wrote in Let the Worms Decide, I decided to do my own experiment on what our composting worms think of junk food.
I began the experiment with the worms "hungry"; I had let the available food dwindle 'way down in hopes of increasing their willingness to accept my offerings. I placed a clean paper towel on top of the moisture mat for greater visibility for the camera; normally their food goes under the mat, but I knew the clever little creatures would find it. From left to right, top to bottom: chocolate chips (60% cacao), a Starburst candy, two gummy bears, two Hallowe'en-sized Twizzlers (strawberry), an Airheads candy, brown rice, a piece of paper towel soaked with local, raw honey, some arugula, and a banana skin.
Four days later, the chocolate chips had apparently begun to mold, and the Starburst was completely covered in it. The other candy had softened and faded, but was untouched. The rice was very popular, but it's hard to tell what they thought of the honey. The arugula showed a small amount of interest, and there was some activity at one end of the banana skin.
After seven days I took pity on the worms and ended the experiment so I could give them a larger quantity of food I know they like. As you can see, there was a lot more worm activity. The rice was completely gone, and there had obviously been a lot of action around the arugula and the end of the banana (note all the worm castings). The chocolate showed a reasonable amount of interest and there were a number of worms around the candy—but they may have been munching on the paper towel. The Airhead seems to have been totally ignored.
It's hard to draw any firm conclusions. The worms can't really eat many items until the bugs and microfauna have done their pre-processing work, and some foods may take longer than others. I don't know why the arugula went so slowly; usually greens go quickly, but perhaps arugula is too "spicy" for the worms—I know they don't like the strong-flavored lemon balm.
I would have thought that the candy, being mostly sugar, should have been easy for them to handle. But I was wrong. According to my Brave browser's AI,
Red wiggler worms should not eat candy. Candy is high in sugar and often contains oils, artificial ingredients, and other additives that can harm the worms or disrupt the balance of the composting environment. While red wigglers can consume a variety of organic matter, including fruits and vegetables, they should not be fed processed foods like candy, cookies, or cake, as these can lead to poor bin conditions and attract pests.
So there you go. Ultra-processed foods are bad for worms, and probably for people, too. Then again, chocolate is bad for dogs, they say, and good for people (in limited quantities), so make your own decisions.
