We've covered some of this sort of stuff here. Junk science is a pet peeve of mine and you'll hardly find an area of science more filled with junk than diet recommendations. I'll link to this piece because it carries a great table of spurious correlations of the kind that show up in what I've called "he-who" studies: "he who eats (or does) X is more likely to get Y;" that sort of thing. There's a great deal of desire on the part of many people to know what they should eat. Simply saying, "eat what your grandparents ate, not industrial foods" which is honestly as a good a recommendation as anything, doesn't get accepted well. The alternative, real, randomized controlled experiments that would last for decades, is prohibitively expensive, hard to do, and nobody wants to wait. As we noted while going through my wife's cancer 24 years ago, it takes five years to get five year survival data; extrapolate that to it takes a lifetime to get life extension data.
The rest of the world does appear to want to institute a carbon tax on meat because of grossly exaggerated figures on the amount of impact animal farming has on methane production. First off, the methane from cows is 1.8% of the greenhouse gas emissions in the US. Second off, methane doesn't come from cattle farts, it comes from cattle burps. I realize that might be a minor distinction, but the EPA, those high priests of junk science, jumped on the "regulate cattle farts" bandwagon under Obama. The UN claims cattle create 18% of global greenhouse gas emissions - more than comes from transportation - but they're lumping in all livestock, not just cattle, to include poultry, lamb and all sources of meat. They're also including the effects of animal feed production, feed harvesting, feeding the animals, the farm vehicles that tend to these animals and everything up to the emissions from the slaughterhouse. A third of that 18% is blamed on deforestation specifically in Brazil.
Both of those summaries are dishonest. First, it's not fair to blame methane production in chicken farming on cattle farming, and it's unfair to include everything that the goes into food production to just the tailpipe emissions of vehicles rather than the equivalent entire life cycle associated with transportation. Second, the part about deforestation is dishonest for two reasons; the easiest being that there's no equivalent deforestation in the US, or in other parts of the world. In the US the story is reforestation. We have more trees today than a hundred years ago. The other reason is that not all grassland could be forest and not all forest can convert to grasslands. There is some relation between the two, but it's not simple subtraction. Simply, much of the planet can't be dense forest and can only be grassland.
Chances are, you've heard until you're subconsciously convinced that low fat foods are healthier. That data was always suspect, but that cynical observation applies that says old science theories don't go away because the weight of evidence pushes them aside; they go away because old scientists who support them die off. Since about 2000 there have been many good quality meta-analyses of all the studies that have been done before and concluded the evidence is just too weak to matter. The diet-heart hypothesis that lifetimes of eating fatty foods and having elevated cholesterol levels led to heart attacks has had conflicting data, like that in older adults higher LDL is associated with longer life, long enough for studies to have essentially concluded the diet-heart hypothesis is dead.
What about vegetarianism? It's another belief that has far more faith behind it than evidence. Seven years ago, I ran a review on a book I'd read by health writer Denise Minger, called "Death by Food Pyramid." Denise was a 17 year old who had thought she should become a raw food vegan but was unaware of the constant effort required to not destroy her health. Vitamin B12, for example, just doesn't come in plant matter, at least not to any level that eliminates the need for supplementation. In Denise's case, she simply needed 17 teeth fixed. At 17, she went to the dentist and after way too many disconcerting "hmm" sounds, heavy sighs, and pokes with pointy metal objects, found she needed to have 17 teeth worked on - coming from never having had dental problems before she became a vegetarian. In the space of one year.
In all of these struggles over diet, we have the same conflicts of interest of special interests that we've had with the Covid fiasco. Everyone pushes to get their favorite industries pushed by the USDA Dietary Guidelines. The vegetarian movement is largely pushed by the Seventh Day Adventist church, and some influential doctors they've won over to their side, like Dean Ornish, a diet book author and M.D., and Walter Willet, the very influential head of Harvard's School of Public Health. The lowfat crowd is pushed by the grain and cereal industry. The push to get people to eat less meat and saturated fat is pushed by the
Someone who has spent the last several years fighting to get the USDA Dietary Guidelines fixed is Nina Teicholz, who went from being a low-fat, vegetarian food writer to an omnivore heading the Nutrition Coalition, an organization trying to get the dietary guidelines to more honestly assess science that has been pouring in within the last 20 years. This an hour long, but very worthwhile talk on many of these topics.
At the risk of overstating the obvious, If a Government Committee Recommends Something, Do The Opposite, as I said here. If they tell you to limit red meat, maybe you should eat more of it.