> Most fast-food chains went to vegetable oils

This is the legitimate end of the spectrum. The science that drove tallow out of kitchens and homes was incomplete, particularly when it was replaced with trans fats.

Where it goes off the rails is when nutters conclude that because tallow was wronged in one context, it is wronged in all of them, which leads to folks rubbing tallow on their faces [1]. (It's probably harmless. I've used it as a foot cream because I got samples at my farmers' market.)

[1] https://www.prevention.com/beauty/skin-care/a63833046/beef-t...

One of the big benefits for corporations is that rancidity in vegetable oils isn't as noticeable by smell, so they can keep using them after they've gone off. Just to add to how much cheaper they are.

Have there been any blind tastings for that? I mean, if people swear by beef tallow's taste, they should be able to also prove it experimentally.

This would also set a level field between beef tallow and other oils. I would expect that a lot have changed in the fast food industry supply chain since the "good old days". Frying oil is only one of the factors that may have affected the taste of fries. Not to mention that everything tastes better when one is young.

"for various reasons" ... not really, the main reason was "supposedly healthier." There was pressure from healthy food advocates, mostly based on pop science claims. In the 1980s the "fat and dietary cholesterol is bad" trend started. That's when restaurants switched away from beef tallow, so they could advertise "fried in vegetable oil" as if that was healthier. They also introduced salads, oat bran muffins, changed from milk to yogurt ice cream, and other things that customers generally didn't want but could be claimed to be "healthy."

The amount of sugar added to prepared food took a big jump around this time, as it replaced fat to make the food taste good. Around this time is when obesity started to become a bigger problem.

That I did know. I lived through the change and "noticeable taste difference" is a massive understatement. What fresh indignity has been injected into the media cycle that makes this in any way relevant?