I'm not anti science, but this is another example of what's called 'scientific truth' changes from time to time. Once they said alcohol is bad, then it turns out one glass a day is good for your heart. And there are so many things that are considered 'scientific truth' out there actually are challenged in other studies.
I remember somebody said something like, "in science, truth is held until a new study shows that it's not true anymore"
The low-carb diet people could point to the way the digestive system actually works.
We should not be surprised to find that in a large population study, no "science" could be found to recommend a low-fat diet to anyone.