Not true. It's better for health and weight loss to stick to requirements for fat + protein and the rest of calories in carbs. you don't really want to go over 50g of fat, around 20-30 is probably best. And that's with pretty much all of it in omega3/omega6 with a 1:1 ratio. A blood test can tell if dietary fat is too low because you will have elevated triglycerides and the doctor will be clueless because nobody eats those levels of fat these days.
That's an opinion which many, including me, do not believe has been backed up by scientific studies.
This is also
how I lost weight, so it's absolutely true. If my carbs go up, so does my weight because I stay hungry all the time. I do eat a lot of fat, too, and my cholesterol levels are pretty enough to frame and display on the wall.

My triglycerides were 52 last time I was tested; standard range is 0-149. My VLDL was 10; standard range is 5-40.
Recommended reading and viewing:
Good Calories, Bad Calories by Gary Taubes
Why We Get Fat by Gary Taubes (a slimmed down version of GCBC)
FatHead by Tom Naughton (video)
The Primal Blueprint by Mark Sisson
Protein Power by Drs. Michael and Mary Eades
One of my favorite parts of
FatHead is a clip of a group of scientists arguing with Senator McGovern about the dietary guidelines that he was trying to push through--McGovern succeeded, which led to the awful advice to cut down on dietary fat and eat more carbs.
Dr. Robert Olson of St. Louis University: I have pleaded in my report and will plead again orally here for more research on the problem before we make announcements to the American public.
Senator McGovern: I would only argue that senators don’t have the luxury that the research scientist does of waiting until every last shred of evidence is in.
This clip kills me every time I hear it because I cannot believe that anyone would say something so monumentally stupid, and yet, here it is on video:
The following article discusses the effects of insulin on diet. I chose this particular article because it was from a more neutral source than ones from paleo/primal or low-carb websites, which I believe have far more accurate information. The focus in this study was specifically refined carbs. However, it is simply a fact that
all carbs trigger an insulin response which is far greater than that of fat or protein, and this is what happens after an insulin response:
How Carbs Can Trigger Food Cravings
Previous research suggests that when blood sugar levels plummet, people have a tendency to seek out foods that can restore it quickly, and this may set up a cycle of overeating driven by high-glycemic foods, Dr. Ludwig said. “It makes sense that the brain would direct us to foods that would rescue blood sugar,” he said. “That’s a normal protective mechanism.”
A low-carb diet is one which is also low-insulin diet, which means that there is less reason for biologically induced cravings. It's just science.