Comment by spacephysics | Hacker News Reader

Comment by spacephysics | Hacker News Reader

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If we hardly know what good nutrition is for humans, how can we assume that meat is some ancillary part of our diet?

This dogmatic view to end meat consumption is a horrible mistake, as it’s predicated on us understanding the human body in its entirety. There’s really no studies that investigate with causality a human diet. It would be unethical/expensive to properly study causality. We have epidemiological studies that find correlation, which has been wrong many times (red meat causes cancer, saturated fats are bad, etc). Epidemiology is meant to point towards a correlation for us to separately study causality, instead of these statistics game of conflating the two via attempting to remove confounding variables.

Further, you’re assuming all land that’s currently used for livestock had no prior use. Much of the land was formally used for crops (until the soil was depleted from poor farming practices, injected with nitrogen/fertilizers, then essentially decimated) if the topsoil was nutrient dense.

Deforestation is needed for crops as well, it’s not exclusively done for animal agriculture. Removing all meat sources would still require some amount of land to fill in the caloric gap. You can’t just subtract all livestock land and say you can plant trees, and thus a net gain.

https://theconversation.com/yes-eating-meat-affects-the-envi...

> It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage.

- Position of the Academy of Nutrition and Dietetics: Vegetarian Diets

The Academy of Nutrition and Dietetics is the largest group of professional nutritionist in the world. People putting doubt that plant-only diets can be healthy are showing the same level of anti-science that climate change deniers are.

The paper goes on to say that having a plant based diet reduces risks of heart disease, type 2 diabetes, and obesity. A vegan diet is one of the most healthy diets an individual can choose when measured by the health outcomes of people that choose the diet.

https://pubmed.ncbi.nlm.nih.gov/27886704/

Sorry but you can't infer 'A vegan diet is one of the most healthy diets an individual can choose when measured by the health outcomes of people that choose the diet' from ' It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases'.

We don't need big studies. Huge swaths of the world are vegetarian. Few cultures are truly vegan, though.

If we hardly know what good nutrition is for humans,

This isn't particularly true. We have a very solid idea of our nutritional requirements.

For instance, we eat (approximately) kilograms of food every day and know about lots of things where we need about 1 millionth of a kg per day.

There's long term health outcomes (like obesity) that we hope to influence using nutrition, but it's likely enough that Pepsi and Doritos (and so on) are the problem rather than some subtle thing. Those products are designed to by very palatable, and to not be overly satisfying (the producers have long since achieved market saturation and increasing individual consumption is a valuable avenue for growth).

I'm not sure where you get the idea that we have a very solid idea of our nutritional requirements. Every few years milk is bad, then good again, then bed again. Some can be said about eggs or meat or coffee or many other foods.

We do know on a very, very granular level that we need some nutrients in some quantities to function at all. But we have almost zero clue on how to actually optimize our nutrition. And the biggest reason is that there are no studies actually trying to find this out.

In that framing, I'm arguing that there isn't much optimization to be done.

It's appealing to think that we haven't even started of course, but malnourishment has become an economic disease.

Do you have any basis for arguing that there isn't much optimization to be done? Food is one of the largest foreign influences on our body, next to air and radiation. It's a wholly untested field so it's surprising to me to say the least to think that there isn't much to gain there.

Take your point on proving causality, but there are interesting selections of populations such as 200K health professionals or SDAs living in LA alongside their neighbors, that go a long way to mitigating confounding variables.

Here is a recent (2018) starting point into large (200k, etc.) studies, with various pooled analysis, meta analysis, RCTs, etc.:

This review summarizes the current evidence base examining the associations of plant-based diets with cardiovascular endpoints, and discusses the potential biological mechanisms underlying their health effects, practical recommendations and applications of this research, and directions for future research.

Healthful plant-based diets should be recommended as an environmentally sustainable dietary option for improved cardiovascular health.

The potentially beneficial role of plant-based diets in cardiovascular health has been increasingly recognized, with a vast and accumulating evidence-base documenting their health effects ...

Most recently, based on a comprehensive review of these studies, the Dietary Guidelines for Americans 2015–2020 included a healthy vegetarian-style dietary pattern in its recommendations of dietary patterns that can be adopted for improved health. In the present review, we will provide an overview of the cardiovascular benefits associated with plant-based diets, while discussing the biological pathways potentially involved, as well as clinical applications and public health implications of these findings.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089671/

See Table 1 for RCTs and Figure 3 for emerging ‘causality’:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089671/figure/...

Also read up on Blue Zones, and note the notion in this meta analysis of...

... the ”pro-vegetarian diet score”, defined by Martinez-Gonzalez et al. (6) as a diet which positively weighs plant foods while negatively weighing animal foods. They conceptualized such a diet as “a progressive and gentle approach to vegetarianism… that incorporates a range of progressively increasing proportions of plant-derived foods and concomitant reductions in animal-derived foods”...

... then think about the blue zones and balance/moderation and confounding variables in that light. It’s not a eating rice or olives or fishing and herding goats from a walkable village, versus sitting on couch watching TV and driving cars to the strip mall thing. Americans act American, so you can narrow down the causality to a kind of temperance.

https://www.bluezones.com/exploration/loma-linda-california/

Diet breakdown with “ancillary” meat: 10% dairy, 4% meat, 1% fish:

https://www.bluezones.com/wp-content/uploads/2016/07/303664_...

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