I've been trying to understand the lipids system (Tom Dayspring) and the insulin-controlled endocrine system (Gerald Schulman). Turns out there's a lot of overlap here (Rob Lustig), mostly around insulin resistance.

There's evidence that dietary fat does not end up in the viscera, also evidence that lots of glucose does not turn into fat via DNLG in the liver - so long as the subject is insulin sensitive.

So, insulin resistance. Schulman has done some fascinating work pinpointing how insulin resistance happens, which is high-fatty-acid related. Lustig has shown how the liver builds up fat in the insulin resistant (some DNLG, some chylomicron FA conversion as it goes to LDL) - and Rick Johnson has shown how fructose, in particular, triggers that reaction, via the 'uricase mutation''. He's figured out when that happened, but the key point is that we hominids would not be around without it.

I think Lustig has the right of it: the issue is simultaneous high fat and high glucose. He also points out that sugar/HFCS is both fat and sugar (fructose goes straight to liver, DNLG to fat, which might be exported, given insulin sensitivity)

Sorry for the long ramble. I'm still trying to assemble all this into a coherent whole, assuming there is one to be found; biology does not work like physics. Gotta say, there are a lot of sidebars I could have veered off into.

Disclaimer: not a medical/bio guy, have just enough organic chem and microbiology to be dangerous. I've just gotten fascinated with this stuff...