Since you're upset about the weakness of these studies, can you point to any that rigorously show any of the claims here? In particular that free range animals are somehow healthier to eat? Grain free next. Followed by the claim that fast food meat is inherently less healthy than meat I can obtain elsewhere.
None of the claims would surprise me if true, but there's a lot of commentary in this post about how flawed these studies are while making very strong claims about what is healthy (no carbs, free range meat, etc).
Getting Hugh quality data with enough power to separate out the effect of Big Macs versus lean steaks is really really hard. I imagine they are doing the best they can with the experimental techniques available to them.
That's why we need large interventional studies instead of observational ones.
Observational studies are interesting and sometimes necessary (e.g. when there's ethical concerns about running an intervention such as with smoking), but it's just way too tricky to separate out the impact of confounders especially when the treatment effects are rather weak (e.g. with coffee or meat consumption).
Most of the conclusions of large scale studies are not very solid and can often be dismissed with correlation is not causation. Your point is valid, but also very often popular health habits align with the view of what a healthy diet is in society. Therefore lower meat intake often is connected to more exercise, more sleep etc. Of course they often try to correct for it, but it still makes many of the conclusions debatable.
There is however one association that seems to hold up for red meat, whether that's a steak or a shitty burger, which is the connection between heme iron and certain form of cancers:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3261306/#:~:tex....
But at the same time the effect is still very small and not well understood.
The biggest problem, most people in the modern 1st world are lazy af. No change in diet is truly going to fix the lack of movement and lack of sun exposure. A 12 hour a day, everyday, call of duty gamer is equally unhealthy and useless whether herbivore, omnivore or carnivore in diet.
We really need to focus on how much sugar is in our foods both naturally occurring but most importantly in processed foods that are everywhere.
I have always operated under the idea that if you only use the produce, meat, and dairy, departments of a grocery store you can do a lot to improve your health. The largess of our society is that we have so many food options that are very easily consumed that many tend towards over consumption; as in no preparation required
Source?