- cross-posted to:
- science@mander.xyz
- science@lemmy.ml
- cross-posted to:
- science@mander.xyz
- science@lemmy.ml
cross-posted from: https://lemmy.ml/post/24943429
Human ancestors like Australopithecus – which lived around 3.5 million years ago in southern Africa – ate very little to no meat, according to new research published in the scientific journal Science. This conclusion comes from an analysis of nitrogen isotope isotopes in the fossilized tooth enamel of seven Australopithecus individuals. The data revealed that these early hominins primarily relied on plant-based diets, with little to no evidence of meat consumption.
We know! Look at that hockey stick in the last 2 million years!
1,2 totally agreed
I’m not making that claim
100%
https://www.dietdoctor.com/low-carb/skeptical-doctors#cancer
The science against meat is inconclusive
Personally I don’t have a opinion about what a adult should eat. Every person is navigating their own journey through health and life and needs to find what works for them. I only take issue with trying to limit people’s options on none causal observational data.
When consumed in moderation it doesn’t always make the hugest difference, but the the claim that “science against meat is inconclusive” is overselling it. Decades of studies show that reducing meat, particularly red and processed meat, in favor of plant-based proteins consistently leads to better health outcomes.
Health Outcomes: Cohort studies like Zhong et al. (2018) found that diets lower in red meat significantly reduce cardiovascular and mortality risks (DOI), while Kim et al. (2016)*linked animal protein to increased cardiovascular mortality and plant protein to lower all-cause mortality. (DOI) Similarly, the BMJ (2020) systematic review showed plant protein is associated with reduced all-cause and cardiovascular mortality. (DOI)
Cancer and Cardiovascular Disease: An umbrella review in PLOS ONE found plant-based diets are systematically linked to lower risks of heart disease and cancer. (DOI)
RCT Support: Controlled trials also confirm these findings. For example, Zeraatkar et al. (2023) found replacing animal protein with plant-based protein improves cardiovascular markers. (DOI) Twin-pair studies further showed improved metabolic health with plant-based diets. (DOI)
Nutritional Adequacy: Plant-based diets provide complete nutrition when planned well. Protein blends match whey in muscle synthesis (pubmed), while legumes and grains promote longevity (DOI, DOI).
https://www.dietdoctor.com/low-carb/skeptical-doctors#cancer
Strong Evidence - Effect of Lower Versus Higher Red Meat Intake on Cardiometabolic and Cancer Outcomes: A Systematic Review of Randomized Trials
Weak Observational - Patterns of Red and Processed Meat Consumption and Risk for Cardiometabolic and Cancer Outcomes: A Systematic Review and Meta-analysis of Cohort Studies
https://www.dietdoctor.com/low-carb/red-meat#cancer
I’m happy you have found a diet that works for you, I have not seen compelling non-observational evidence that ASF is dangerous, ESPECIALLY in the context of a low carbohydrate diet. I’m not trying to change your mind, but I wanted to illustrate that different reasonable people reading the literature can come to different conclusions.
Good prospective cohort studies and meta-analyses of them are some of the best evidence we can possibly get for diet, because doing lifespan-scale human RCTs is completely impractical, especially for diet. The meta analyses you shared still showed an association between reduced meat consumption and reduction of CVD risk, just with low effect size and low statistical confidence, so this is really not strongly contrary to the conclusion that red meat is better to eliminate or reduce.
I hear the “correlation is not causation” argument loud and clear, but meat is expensive, meat consumption correlates with wealth, and wealth correlates strongly with health and longevity. Diets like the Atkins diet and the Paleo diet have also been relatively popular among health-conscious people since the 70’s. The animal agriculture industry also has enormous incentive to fund studies which show animal products in a positive light. So I really don’t see any strong reason to think that confounding factors/biases would systematically favor low-meat diets rather than high-meat diets. If meat were truly neutral in terms of CVD risk, we would expect to see a near equal number of studies showing that it is protective for CVD as we see studies showing it increases CVD risk, but this is not what we see in practice.
RCTs measuring CVD biomarkers also pretty consistently show that reducing meat consumption, especially red meat, decreases well-established CVD biomarkers, so, if these results combined don’t convince you, what results would convince you?
And yes, the evidence for cancer with unprocessed red meat is weaker, but the evidence for CVD risk and CVD biomarkers is pretty consistent across both RCTs and observational studies. The small effect size you mention is consistent with the expected heterogeneous results of some studies, and the fact that the effect size is weaker than something like smoking does not mean the effect does not exist.
The CVD hazard ratio may be close to 1.11 for red meat, which means just 100g a day increases your risk for CVD by 11% (Red meat consumption, cardiovascular diseases, and diabetes: a systematic review and meta-analysis). In an animal based low carb/carnivore diet you would need to be eating 10x that much (whether or not youre incorporating other animal foods also high in saturated fat), and there’s no compelling reason to expect the results to be better by consuming more of something with demonstrable long term cardiovascular system-damaging effects, whether in the context of an extremely low carbohydrate diet or not. Studies like Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis also show us that a moderate level of carbohydrate consumption give better results than either extreme high carbohydrate or extreme low carbohydrate diets. “There was a U-shaped relationship between carbohydrate intake and mortality in the Atherosclerosis Risk in Communities cohort, a finding that was consistent in the meta-analysis combining these data with those from the other cohorts. When assessing total carbohydrate without regard to specific food source, diets with high (>70%) or low (<40%) percentage of energy from carbohydrates were associated with increased mortality, with minimal risk observed between 50–55%. Low carbohydrate dietary patterns that replaced carbohydrate with animal-derived protein or fat were associated with greater mortality risk, whereas this association was inverse when energy from carbohydrate was replaced with plant-derived protein or fat.“
What you define as “dangerous,” is somewhat subjective, but if you care about things like minimizing all-cause mortality and heart disease risk (which you probably should, given that CVD is the number 1 killer), then it’s pretty clear that eating ASF in large amounts is suboptimal.
May I see these RCTs please? What do you consider a CVD biomarker? Not LDL hopefully. CAC scores, insulin resistance, or all cause mortality please.
I do not agree with this, a abundance of weak observational studies do not make causation. But the point of this discussion isn’t to get us to agree, just to indicate that people well versed in the literature and looking at the evidence strength would not agree that the evidence is overwhelming… which is to say there has not been a casual link established.
The study Meta-Analysis of Randomized Controlled Trials of Red Meat Consumption in Comparison With Various Comparison Diets on Cardiovascular Risk Factors analyzed 6 RCT’s that compared red meat to plant-based protein sources and finds that the plant-based protein sources consistently result in better blood lipids and lipoproteins compared with red meat:
As to your comments about CVD markers, there are of course contrarians, but the evidence linking both LDL-C and apoB with CVD risk is strong. Look at mendelian randomization studies for both.
https://link.springer.com/article/10.1186/s12916-020-01792-7
https://www.neurology.org/doi/full/10.1212/WNL.0000000000007091
https://journals.plos.org/plosmedicine/article?id=10.1371%2Fjournal.pmed.1003062
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2814089
Substitution of animal with plant protein lowers apo-B https://www.ahajournals.org/doi/full/10.1161/JAHA.117.006659
In comparison with control diets, plant-based diets improved Homeostatic Model Assessment for Insulin Resistance https://www.mdpi.com/2072-6643/16/13/2110
All cause mortality was reduced by plant-based diet in the meta-analyses of prospective cohort studies I shared earlier, nobody tries to measure that for dietary RCT’s…
Low carb diets high in animal products result in increased CAC scores and the animal-based but not plant-based LCD score is significantly associated with a higher risk of CAC progression (animal-based LCD score: hazard ratio, 1.456 [95% CI, 1.015–2.089]; P=0.041; plant-based LCD score: hazard ratio, 1.016 [95% CI, 0.821–1.257]; P=0.884 https://www.ahajournals.org/doi/full/10.1161/ATVBAHA.120.314838 (observational)
Does the “us” in the graph imply that carnists lost a significant amt of brain size?
Better graph. The only data I’ve seen on modern brain size differences would be due to vitamin deficiencies.