site disappeared from serps

I had a site that was ranking at around 13-15 for a relatively high competition keyword in the weight loss niche for the past 2 months. Then just the other day it disappeared completely from the serps overnight (at least not in the top 100). However, the site is still indexed. No new links were added to the site recently so I have no idea why that would happen.
Anyone here care to speculate on the cause?

This.

Can discuss here.

Payday vengeance baby.

Yep, I'd put your niche into the payday loan algo they just updated.

Probably a mixture of your backlinks and the niche you are in.