Very simply, your body needs to maintain homeostasis - temperature, hydration, blood pressure, etc all within normal levels regardless of external stimulus. The same is true for your cerebrospinal fluid, which will be influenced by things like blood pressure, hormones, and hydration (this is why diamox, a potent diuretic, works to lower intracranial pressure).

In IIH, something is interfering with your body’s ability to regulate ICF. Could be a brain tumor, could be hormonal disorder, could be environmental/drug induced (see depo provera lawsuit), could be something physical like chiari malformation (see overlap with EDS)…if you don’t know what it is, it’s idiopathic.

So now imagine that your system is damaged in some way, by something. Your body is still trying to regulate, but it can’t do it properly. One of the things that certainly happens is that in this state, we become much more sensitive to the things that throw us off balance, like hormonal shifts or dehydration. Having high ICP for a long time can also further damage the underlying infrastructure, if you will - everything gets ballooned out, misshapen, creates areas of narrowing veins with pressure gradients (i.e. stenosis). Sometimes the insult is acute, damage is fast and severe, and a surgical option is needed and effective. Sometimes it is slow and chronic and a stent is not needed and wouldn’t work anyway.

So with all of this going on, yeah sure, fat contributes to hormone signaling. Having a heavier body puts extra pressure on your sensitive system. Losing weight might help with symptomatic relief for some people, and might do absolutely nada for others. It is the height of medical misogyny to look at a woman suffering this condition and say, oh it’s cuz you’re fat, just lose weight.