The studies that looked at whether cutting back on saturated fat is healthy are all kind of sloppy—they didn’t plan ahead properly, and none were done well enough to trust their results.

Some big studies that looked at lots of people who ate less saturated fat didn’t find that they lived longer or had fewer heart attacks, which makes people question why we’ve been told to avoid foods like butter and cheese for so long.

We can’t be sure if saturated fat is good or bad for you because the studies are all over the place—some say one thing, others say the opposite, and the measurements aren’t very accurate.

Before the government told everyone to eat less fat, no study had actually tested whether eating exactly that much fat helped people live longer.

Scientists aren’t very confident in what they know about how saturated and trans fats affect health — more research could easily change what we think today.

Most of the old studies on cutting saturated fat were done on older men who weren’t taking cholesterol meds, so we can’t be sure the results apply to today’s diverse patients who often take medication to lower cholesterol.