Quote from tim on March 3, 2023, 10:05 pm

The existence of salivary amylase (does not directly indicate the amount of starch consumed; polar bears have genes that encode for salivary amylase; nobody is arguing whether humans ever ate starch, the question is how much, and what evidence we have suggests not much)

Humans produce a significant amount of salivary amylase. Carnivores don't eat starch, omnivores do so you are acknowledging that humans are omnivores. Polar bears are descended from omnivores so of course they have those genes but they do not produce significant salivary amylase.

Amylase being the primary enzyme produced by the pancreas (how are you defining "primary"?; cats have a pancreas and they are obligate carnivores, so the pancreas obviously serves critical functions outside of starch digestion)

The human pancreas produces more amylase than protease and lipase.

The differences between humans and carnivores with regards to gluconeogenesis abilities (humans didn't need the same level of gluconeogenesis when they had abundant access to animal fat, which appears to be the case until relatively recently in geological time; do you see Shawn Baker keeling over from lack of energy on his rowing machine or Anthony Chaffee collapsing on the rugby field?)

Sport is very competitive, if a carnivore diet was optimal most top athletes would already be on it. Most cells prefer glucose, ketosis is not the optimal metabolic state. In glycolysis most cells use glucose but fatty acids and ketones are also available. 

The existence of teeth designed for chewing plant foods (we have the dentition of an omnivore but we don't have the jaw musculature for eating fibrous plant material; once again, nobody is arguing that humans have eaten plants, the question is how much and was it necessary when animal food was available, and the best available evidence points to very little and no we didn't need it when animal food was available)

We are processed cooked food eating omnivores and our dentition matches that. The evidence points to humans always having sought out sources of sugar and starch in their environment. But even if most humans had low carbohydrate intakes in the last Ice Age it doesn't mean that that is optimal for modern humans and it certainly doesn't mean that a meat only diet is optimal.

Human instinct to also consume starch and sugar when given the opportunity to eat only meat (this is only an argument against obligate carnivory, and nobody is arguing that humans are obligate carnivores; we are facultative carnivores)

A wolf is a facultative carnivore, humans are omnivores. Millions of humans have lived long healthy lives eating very little meat.

Every human group eating omnivorous diets for all of recorded history (if by "omnivorous" you mean eating even the tiniest shred of plants, yes, but that is an absurd definition of omnivory...even cats meet that definition; there are a number of extant indigenous groups that include inconsequential amounts of plants in their diets; all of recorded history (depending on how strict your definition) falls within the agricultural period of modern humans...confounding factor possibly?)

Inuit are an argument for humans being omnivores because there is evidence that they've made genetic adaptations to their diet such as enhanced gluconeogenesis. They also sought out plant foods where ever they were available: animal stomach/intestinal contents, berries, seaweed, roots/tubers and caches of seeds stored by rodents. There isn't evidence they were healthier, more athletic or had more longevity than tribes in the americas living at lower latitudes.

Omnivores can have the ability to live on a highly carnivorous diet but it's usually unlikely to be optimal for them.

The closest species genetically to humans chimpanzees being omnivorous (this doesn't matter one bit, and if you understood evolutionary biology you would know this...chimps are not capable of throwing projectiles at high speed or bipedal sprinting despite being genetically similar to us)

Of course it matters that no great ape is carnivorous. You argue that omnivorous human diets are sub optimal because of a belief about what we ate historically but want to dismiss the fact that early in our evolution we almost certainly consumed an omnivorous diet for millions of years.

Human nutritional requirements e.g. carnivores produce vitamin C endogenously, humans don't (we can get the tiny amount of Vitamin C we require from animal foods, and there is evidence to suggest that the role of Vitamin C was replaced by uric acid or other antioxidants that are derived from animal foods; regardless, carnivory is not defined by the endogenous production of Vitamin C)

The evidence is that optimal vitamin C intake is higher than that from consuming a meat only diet.

Most of these points revolve around facultative carnivory vs obligate carnivory.  Nobody said we were obligate carnivores, we're not.  We are facultative carnivores who need meat and thrive on just meat (I'm talking about the species as a whole, there are going to be rare exceptions due to damage incurred during life or inborn genetic errors).

Wrong, we thrive on an omnivorous diet.

You believe in the published literature and only the published literature, and yet you don't seem to understand the weaknesses of the published literature.  There's also only a single study published on modern carnivore diets (which showed improved outcomes).  Until there is a study that shows worse outcomes on a carnivore diet, you have no grounds to say that it doesn't work based on the literature, because every other study you're going to reference has piles of confounding variables.

Wrong, maybe these assumptions are your way of trying to make how biased you are less obvious. Imagine placing the burden of proof on those that do not accept a carnivore diet as the only way, the true way, the holy way.

You haven't even tried a carnivore diet, whereas I have tried all kinds of diets short of veganism/vegetarianism and have consulted with practitioners across the dietary spectrum.  As a wildlife ecologist who's personally researched and published on predator-prey dynamics, I've also spent a lot of time studying and thinking about the consequences of different evolved dietary strategies and how they relate to energetics, morphology, and ecological niches.

You don't know what I've personally tried. None of this adds to the strength of your argument.

"You're completely missing the point which is that I'm not appealing to authority and nobody is appealing to me as an authority. You and Jeremy are appealing to Cho as an authority. You've also just admitted you know nothing about her credentials which are bogus."

Nobody said you were appealing to authority, christ!  I already explained that Jeremy and I are not appealing to authority either.  I can't make it any more clear.  We are not citing Judy Cho per se, we are citing her work.  Just because you think she's a liar does not mean we are using an appeal to authority argument.  We tentatively make the assumption (which could be falsified, but is not yet falsified) that she is not outright lying, the same way that you trust whatever you read in scientific publications without having seen the original datasets or having knowledge of the statistics or study design required to judge the veracity of the authors' statements.  The difference is, you trust a system that is known to be corrupt.

You're confused and not saying anything here that refutes what I previously wrote. You're not citing her work, you haven't cited anything. All you are doing is making claims about her claims.

You're the one referencing studies and specific people's work here. So Judy Cho's claims are rock solid but science as a whole is so corrupt that we can't even trust basic knowledge on physiology?  Do you believe that there is a multi decade conspiracy to convince people that humans produce lots of amylase when they don't? Why are you even here discussing concepts that are scientifically derived if basic physiology can't be trusted?

"Nonsense. A rebuttal involves responding directly to the points of the other party and explaining why they were wrong. Imagine thinking that parroting claims one unqualified woman is making is a rebuttal to my statements about basic physiology, makes no sense. Then imagine accusing me of regurgitating information."

You just don't accept the rebuttal because there's not a published citation.  Guess what, not everything is published!  Why do you think new things are published every day?  Because we learn and realize that our old models are wrong.  There is a single modern publication about people on carnivore diets (https://academic.oup.com/cdn/article/5/12/nzab133/6415894?login=false) with a reported 95% increase in perceived overall health.  It's not a well-controlled study, but if you're going to wield all the other bullshit dietary studies out there in your favor, you'll have to accept this one along with them.

"No I'm not. Unless sound evidence is published of results she is getting it's just anecdotes and the opinion of someone that isn't a sound authority. Anecdotes that contradict actual authorities. This is all just word gymnastics though resulting from extreme fad diet dogmatism and it doesn't matter if this lady is turning water into wine it has nothing to do with my initial points."

You do realize that all the dietary recall studies that got published are technically collections of anecdotes?  Nobody watched what these people were eating every day of the study.  Oftentimes, they ask them to do a 24-hour food recall only once every few weeks for a study that runs for months...talk about shitty data, and that's what a lot of your arguments rest on.  Like I said before, you have no idea how shaky your foundation is because you don't understand the in's and out's of peer-reviewed journal publications and academia.

You keep claiming how ignorant I am about science while directly exposing your ignorance about it. You keep writing strawmen about me relying on dietary studies to make my case about humans being omnivores. Please point out where I am relying on dietary studies to make my case?