From 1995 until around 2000 I followed a very low fat vegan diet. The target was to achieve < 10% calories from fat. Kris Gunnar over at Authority Nutrition has a typically well researched blog post summarizing the known effects of a low fat diet.
Leaving aside his effects 1 and 3, which are argubly inputs rather than effects, I have evidence for: increased triglycerides (effect 2), decreased HDL (effect 4), and Pattern B LDL particle size (effect 6). I suspect, but have no evidence for reduced testosterone levels (effect 6). And I haven't had a heart attack or stroke (effect 7), yet. To be fair, I don't know if my off-scale results on LDL particle size are a result of genetics or my diet, or both, because I don't have measurements from pre-vegan days. But I can assure you, my results now are bad!
In the year 2000 I decided to stop worrying about fat so much, because with two growing children it was a pain cooking differently for them and for me. I also added eggs back into our diet, because a free range egg is a nutritional powerhouse with few ethical strings attached. At the time my total cholesterol levels were very high, high enough that my doctor in Oz wanted me on a Statin. Guess what happened when I started eating eggs and increased my consumption of fat? My total cholesterol went down. That's right. Down. Not up. Did that ever rock the paradigm! Of course it didn't stay down, but that's a story for another day.