Comment by hilbert42

Right, one has to ask the obvious question why do we need yet another study to prove the bloody obvious when we knew decades ago it's calorific intake that's the principal culprit in obesity.

Well, here's the likely answer. This story appeared on HN some hours ago: https://news.ycombinator.com/item?id=44648728.

Many (including myself) had come to a similar conclusion about this and other controversial matters such as climate change ages ago, which is that these studies into the obvious/long-resolved facts are conducted to try and convince the skeptics and disbelievers with even more irrefutable solid evidence.

That article puts a very convincing case that that approach is not only a waste of time and effort but it's probably counterproductive—trying to convince those who've entrenched beliefs and or find the truth painful only makes their positions even more entrenched.