Long-standing fears about fat’s impact on heart health seem to be dissipating: today, fat is in and it is carbohydrates, sugars and processed foods that are out.
...but most of the satured-fat fear is pretty outdated/debunked as far as I can tell?
Also, here we go, JAMA Internal Medicine long-run massive study:
those people who ate the most butter (averaging around one tablespoon per day) had a 15% increased risk of mortality compared with those who avoided the stuff. By contrast, people who consumed the most plant-based oils, such as canola, soyabean or olive oil—all of which have low levels of saturated fat—had a 16% lower mortality rate than those who consumed the least.
At the end they quote an epidemiologist objecting to an obvious problem with the study:
the voracious butter-eaters contained twice as many smokers, for example, as the butter-avoiders. He argues it is not possible to fully control for such differences, which means some non-dietary factors could be at play.
Like what... you do this massive, 33-year long study and don't control for smoking...? WTH.
Nah, I'm out: full butter nerd over here.
non-paywall here: https://archive.md/cCLjC