The whole low-fat thing is a lie, it should have been sugar in the frame, not fat.
Yes, really.
The anti-eating-fat idea began when US President Eisenhower had a heart attack in the 50s. His doctor advocated the new idea that a high-fat diet causes heart attacks, based on the ideas of an eminent scientist at the time. The scientist didn't have any evidence, it was a theory, but these three powerful men - the President, his doctor and a well respected scientist - wenton a misguided crusade to educate the public that eating fat is bad for you.
The scientist later did a study to back up his claims, but it was not scientifically rigorous. For example he looked at data from many countries, but did not include those that he knew had a high fat diet but low heart disease.
But, his ideas were accepted and have been taught to us all as fact since.
In the 70s a UK scientist suggested that actually it was sugar not fat that was the real issue. He was absolutely vilified, he lost his job, status, ability to get funding for his work or his papers published. So viscous were the attacks from the nutrition science community that no one else dared challenge those ideas again, until recently.
And the thing is, if you go back over the data in the study that "proved" fat is bad for you, a much higher corolation was found between sugar and heart disease, but the scientist choose not to report that (probably for ego reasons)
So all those low fat diets, all that feeling we're failing to shift weight when we should be. all of it, was based on one guy's attempt to further his career without a proper scientific basis, and the way nutrition science has supported dogma over facts.
Basically sugar gets turned into fat in the body. That's the real culprit.
There's a reason low-fat diets are not working! It's hokum!
Ditch the low fat, eat real food, cut out sugar, exercise.
Here's an article on it, bit of a long read but fascinating The Sugar Conspiracy - Guardian article