Then, just like now, unscrupulous product marketing and media mistates medical consensus or ascribes consensus where there there is none. Just look at Snackwells. The product marketing term "Doctor recommended" does not mean all doctors, or even specialists in the relevant area.

Unless you are talking to a physician or reading a medical journal, anyone should assume that someone claiming to talk about what the medical community believes is probably wrong and possibly lying.

In the context of the current conversation, reducing saturated fats and bad cholesteral was a reactions to this epidemic https://pubmed.ncbi.nlm.nih.gov/24811552/

After peaking in the mid-1960s, the number of heart disease deaths began a marked decline that has persisted to the present. The increase in heart disease deaths from the early 20th century until the 1960s was due to an increase in the prevalence of coronary atherosclerosis with resultant coronary heart disease, as documented by autopsy studies. This increase was associated with an increase in smoking and dietary changes leading to an increase in serum cholesterol levels