The funny thing is... maybe?

There's some evidence that the absence of parasites might be a contributing factor to autoimmune diseases, asthma and inflammatory disorders. See: https://www.verywellhealth.com/helminth-therapy-5225248 for an example.

Unironically, it might. Many people suffering from IBD have found relief by ingesting certain parasites (helminth is one I’m aware of). To add anecdotal evidence to the parent, I’ve found relief with my IBD by eating “simpler” foods - on top of overall health benefits.

Chesterton’s fence is not a well respected concept in the modern world (understandably so).

How else are ya gonna lose weight, fatty? That tapeworm can't feed itself.