Low body fat can certainly cause your periods to stop, regardless of your diet.
There are reasons your period stops that are unrelated to body fat -- I have a relative with empty cella (sp?) syndrome, which basically means her pituitary gland no longer functions. One result was no more periods; her doctor told her it was early menopause, but by seeking a second opinion she found out the real reason.
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles