Worms Eat Their Own Weight in 2 Days

You will read variations on this throughout the literature.
My understanding is that Mary Appelhof, in writing her original book, needed a figure and made a good guess with the half-their-weight each day.
Since then everyone quotes it as gospel. I wouldn't be surprised if Mary was a bit embarrassed.
As a starting-point for calculation, it is not bad. As a rigid rule, it can easily be shown to be in error. See the section "Food Weight" for details.
For a novice, I'd suggest under-feeding the worms rather than risk over-feeding.

Start low and raise the bar.

The main failure in vermicomposter bins with new users seems to be in assuming that the entire kitchen scrap load can be stuffed into a small bin. I've heard horror stories of complete cabbages being buried.
Try adding a handful of scraps each day, or every two days, then over a period of a month, increase the addition ever so slightly. If not all the food is being digested, it may be time to start a second bin.