If it clears arteries near the heart, it probably keeps other arteries clear too.
Good blood circulation is crucial. Lots of things in your body are crucial, but good circulation *really* is. It probably helps keep your brain working well; a lowfat diet helps preserve people's hearing in old age, I've heard, because of good blood circulation in the ears; prevents strokes, and on and on ...
The supposedly heart-healthy monounsaturated fat, the fat that's in olive oil, may not be so healthy after all. Rudel did some experiments on monkeys that showed monounsaturated fat caused atherosclerosis just as much as saturated fat. Monounsaturated fat is thought to be heart-healthy partly because it doesn't do bad things to blood lipids, as saturated fat does. But Rudel found that it enables the transport of cholesterol from the liver to the heart, causing atherosclerosis. From experiments on mice, he thinks this mechanism is probably the same for all mammals.
Polyunsaturated fat causes cancer in animal studies. It's not clear whether it does in people.
And perhaps polyunsaturated fat in processed food is slightly rancid by the time you eat it. Polyunsaturated refined oils are exposed to heat, oxygen and light during refining, which tends to oxidize them (make them slightly rancid). Rancid fat is a carcinogen, I've heard.
Would animals that get cancer from diets high in polyunsaturated fat, still get more cancer from a diet high in whole nuts and seeds?
There are hundreds of studies showing the benefits of the omega-3 fats EPA and DHA, though. You only need maybe half a gram or a gram of EPA/DHA per day, so it's easy to still have a low-fat diet. I use EPA/DHA made from algae , because I get sick from fishoil capsules.
Dr. Ornish also showed that his very lowfat diet of fruit, vegetables, and legumes, with omega-3 supplements, tends to reverse prostate cancer and may help prevent cancer in general! He says he's pretty sure the Ornish diet would also be helpful in breast cancer.
You get used to whatever amount of fat you eat. I don't find a very lowfat diet to be depriving at all. I'm not tempted to eat high-fat foods. I gradually cut down on high-fat foods, over months. Cutting down gradually makes it easier.
And of course a lowfat diet is more bulky, thus may help people lose weight, especially if it's also low-fructose. I think this is the way to get slim and stay slim with a minimum of stress. Cutting out unnecessary fat and protein is an easy way of lowering caloric intake while still getting adequate nutrition, which slows aging.
The high-starch diet gives me a lot of energy, too.