He just want to be fit. There are many ways to lose weight but putting worm and eating dirt are not one of them.
Yes, I understood the rationale; just found it bizarre that TVB would write something so disgusting into the script, LOL... Besides worms like that usually don't come as a singular entity, if there's one there's more than likely a whole bunch. He would need an anthelmintic to be rid of them. What's more, you notice that he's using two toothbrushes to replant the worm; since people only use one toothbrush, one has to realize that one of those toothbrushes can't be his. Imagine living in that family where another member uses your toothbrush to pick up a worm from his shit to stick back into his ass? This is a new low, even for TVB. The whole thing is just EWW...
Slow to start, but after a fashion, starts to grow on me and I'm finding it interesting and engrossing. Can't wait for the next ep, LOL...