'Old' in the sense that low carbohydrate, high fat diets have been known about for a century or more as a way to treat autism, and in the sense that there are s

'Old' in the sense that low carbohydrate, high fat diets have been known about for a century or more as a way to treat autism, and in the sense that there are studies from the middle of last century which replaced saturated fat in peoples' diets with seed oils which showed no benefit or even increased mortality. Some of these studies were botched or cherry picked their data to support a conclusion that saturated fat is bad for our health, but upon re-analysis have shown no such effect. See for example the Sydney [1] or Minnesota [2] heart studies. The confusing aspect with these studies is that frequently they show a decrease in cholesterol when switching to seed oils, and conclude that seed oils must be healthier than saturated fats, but it turns out that cholesterol levels have very little to do with overall health (sorry for the unsubstantiated claim - I don't have a good reference to hand, but I can look it up if you ask - usual caveats apply: I am not a doctor etc. etc.). [1] https://www.fasebj.org/doi/abs/10.1096/fasebj.27.1_supplement.127.4 https://www.fasebj.org/doi/abs/10.1096/fasebj.27.1_supplemen... [2] https://www.bmj.com/content/353/bmj.i1246 https://www.bmj.com/content/353/bmj.i1246