Nah that’s actually a myth itself. Pure sugar serves no purpose (in an otherwise healthy diet) and causes or exacerbates many minor health problems. It can make some kinds of arthritis go on the fritz and of course can directly contribute to (to the point of being a direct cause of) diabetes.

Similarly, saturated fats are much, much, much easier to get way too much of, which makes them worth avoiding.

There are a few other food components that are absolutely not healthy, but I don’t remember specifics off hand.