Hengist et al publish a toy paper where they fed 14 guys pizza and ran a blood panel. Sure, why not. Probably took an afternoon, and was real cheap to do, gave some of his grad students publication credits and LaTeX experience. We learn that eating a pizza will not instantly give you diabetes, or make you obese, which we already knew. This, by itself, is fine.
Separately, the University of Bath has a press office which is required to issue a certain number of press releases per year, even when the research isn't interesting. Again, no real problem. Plenty of press releases are issued with nobody ever reading them. If the University of Bath wants to employ people to do nothing useful, that's their own business.
This press release is submitted to HN and gets a bunch of upvotes. Problem. People in the comments try to generalize the study. Big problem!
The paper had no followup, no dose schedule, tiny experimental groups... because it wasn't trying to solve obesity!
Nobody knows what's causing the obesity epidemic. There are many hypotheses, all with holes and strange contradictions. There have been many gigantic studies, all with inconclusive results.
There is no reliable way to lose weight.1 There are many diets that work for some people, all with holes and strange contradictions. There have been many gigantic studies, all with inconclusive results.
This is a nice little toy study. I don't doubt the data or the results. I just don't think it's useful. And studying obesity certainly isn't like running a randomized clinical trial on if beheading will kill a person!
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1: Yes, if you lock someone in a cage and not give them food, they will lose weight. Obviously. Once you release them back into modern society, they will regain that weight.
Correct me if I'm wrong but that is false. It seems pretty well known and accepted that caloric intake below BMR will make you lose weight. Your BMR might fluctuate, but if you take that into account there shouldn't be a problem.
Going back into society and resuming your previous eating habits (before the cage) will ofc make you gain weight because your BMR will have lowered during your starvation.
A targeted public health intervention that prevented beheadings just at the time of beheading would clearly break the link in the causal change. This result is insensitive to any imaginable confounders. However, the executioner would find another strategy, say a gunshot or noose, which did not appear anywhere in our dataset.
Really makes you question the validity of observational studies. At least when acts of government are concerned.
In OP's paper, I'm not sure if they met this criteria.
Sure, if you measure the time surrounding the beheading, it's obvious, but if you expand the time range far enough, then you find out that everybody dies whether they're beheaded or not and suddenly it looks irrelevant.