Eating an apple a day - unsupported
Saturated fats causing increased cholesterol, thus leading to heart failure - unsupported
It seems that almost everything we've been told since childhood to be healthy has no scientific basis whatsoever.
It's pretty indisputable that fruit and vegetable consumption reduces CVD, increases mental well-being, and lowers weight.
> Saturated fats causing increased cholesterol, thus leading to heart failure
Previous evidence certainly overestimated the impact of saturated fats, especially vis-a-vis processed carbohydrates. However there's no doubt that saturated fat still increases CVD mortality vis-a-vis unsaturated fats.
One of the biggest pitfalls in thinking about nutrition is asking "is food group X good or bad?" The real question is food group X good or bad in comparison to what? After all if people reduce the percent of X in their diet they have to replace it with something else. Beef is "good for you" if the marginal substitute is cupcakes, but "bad for you" if the marginal substitute is salmon.
[1] https://www.bmj.com/content/349/bmj.g4490.full.pdf+html [2] https://www.nature.com/articles/0802795 [3] https://ajph.aphapublications.org/doi/full/10.2105/AJPH.2016... [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5475232/
Filling out your meals with more plant based foods instead of avoiding those foods while eating lots of low quality meat will have measurably better outcomes:
I'd dispute part of that -- fruit contains significant amounts of sugars, and eating a lot of fruit will result in weight gain.
Eating a lot of vegetables is almost definitely a healthy option, and weight gain is unlikely.
It can also absolutely be the case that old recommendations were a mix of old wives tales (with no scientific basic whatsoever), bad papers (replicated and taken as gospel without reproducibility and further study) and studies sponsored by the food industry to promote this or that foodstuff...
I figure you may as well.
Recently, I have read an article which claimed that one should only drink water when their body demands it, you know, like becoming thirsty. The problem is, in most of the popular science circles these kinds of urban myths are propagated almost as if they were basic nutritional facts. I would personally think some mega-companies, such as Nestle, would be really interested in propagating the myth of the necessity of consuming at least two liters of water.