Hacker News Reader

Wow, I found this cool PDF of a document from 1917 which has calories yields per acre. It's incredible how much yields have increased in 100 years.

It records Pork at 672k calories per acre

https://naldc.nal.usda.gov/download/ORC00000242/PDF

EDIT: Another great quote from the PDF "The soy bean.—Soy beans lead all other crops in the production of digestible protein, exceeding corn in this respect by almost exactly 100 per cent. This crop deserves more attention in this country than it has yet received. There is no reasonable possibility of overplanting it. "

I think you are missing something very obvious which cannot be captured by a technical analysis of calories per acre.

Who on earth is eating broccoli for the calories? Assuming 34 calories per 100g that would mean I would have to eat 6kg of broccoli every day to reach 2000 calories. I'm not going to exclusively eat broccoli.

Let's go with a slightly more realistic scenario: I have an absurd love for broccoli and eat 50% corn and 50% broccoli (weighted by calories). 15 million calories50% + 2 million calories50% = 8.5 million calories per acre.

As soon as someone gets less than 50% of their calories from broccoli the Pork starts to look very inefficient.

Well, you're missing the part where many acres of vegetable crops are inputs into that single acre of pork, so how are you going to compare an acre of pork back to an acre of vegetables as if it just comes out of thin air? For example, 60% of crops in the USA are fed directly to animal ag.

Animal meat is nowhere near as efficient as eating vegetable crops directly. It concerns me how long you've been spouting your claim with such an elementary error.

> Well, you're missing the part where many acres of vegetable crops are inputs into that single acre of pork

What do you mean by vegetable? It is a rather loaded term. Culinary vegetables are definitely not fed to pigs in any meaningful quantities. They are much too inefficient to even consider. If by vegetable you mean any kind of edible plant, then yes, pigs are fed mostly very-efficient-to-produce corn and soybeans.

Based on the numbers before, when you feed pigs 15 million calories of corn (1 acre), they give back 3.5 million calories of pork. If you fed pigs 2 million calories of broccoli (1 acre) then they would likely only give back 0.4 million calories of pork. But that's a really big reason why you don't normally feed pigs broccoli.

> Animal meat is nowhere near as efficient as eating vegetable crops directly

Agreed, if you are talking about the specific vegetable the animal is eating. However, vegetative efficiency varies greatly from crop to crop. If you feed animals the most efficient plants, then they can still be more efficient overall than the less efficient vegetables are alone. As before, the food the animals eat is, for all intents and purposes, not the same food that you eat. Plants that are intended to be fed to humans are generally less efficient to produce, for various reasons.

Because OP truly could not have included the number of acres required to support pork in the 'acres of pork' figure?

It sounds to me like he did include the crops fed to pigs in the acreage

How could that conversion work while respecting the second law? Here’s a good breakdown on the subject: https://stanfordmag.org/contents/can-vegetarianism-save-the-...

Factory farms help with the numbers. You can keep pigs more dense even if they don't depend upon the area for the source of feed - just like humans and urban density. A high density in 1 acre ks perfectly plauisble but it ignores the feed crop acres. At that point efficency should be total crop calories * pig efficency margin (10% for standard trophic level to back of the envelope) / (acres of corn + acres of pig).

If you took the density scale to something really absurd the pig acre efficiency would be the crop times the multiplier as that space converges eventually converges to becomes negligible and just "pig efficency * feed crop calorie/acre" effectively. Granted the effective convergence point may not be realistic without real world data but if factory farms are big enough it comes out to the same order of magnitude as brocoli about 1.5 vs 2. Of course there are a lot of other things to legitimagely object to about said arrangement but it surpringly lines up to be comparable to vegetable crops in caloric efficiency.

A more in depth answer would look at the caloric share of diets in consumption - most people don't get their bulk calories from vegetables.

> If you took the density scale to something really absurd...

> Of course there are a lot of other things to legitimagely object to about said arrangement...

The sad reality is that the density scale at pig factory farms is already well past morally objectionable territory if you are concerned at all about animal welfare. I’ve linked resources on this before and can do so again if desired, it’s horrible stuff.

Pigs are about the same as dogs in their sentience and even suitability as a pet. I don’t see how one can justify caring for a dog as a pet and also buying factory-farmed pork once they learn about it. Small farms with better living conditions are arguably more justifiable. I don’t eat animals any more, stopped for different reasons, but being aware plays a role in keeping me from going back.

> How could that conversation work while respecting the second law?

Well, if you start with 15 million calories worth of corn, feed it to pigs, and you get 3.5 million calories of pork back out, the rest of the energy is exerted to keep the animal alive through its life. The second law is respected.

Meanwhile, an equivalent acreage of broccoli only provides 2 million calories, being far less efficient at converting the environment's resources into calories than corn, so it is starting from behind and never makes up for just how efficient corn really is. The second law continues to be respected.

If you fed that broccoli to pigs, you might not even get half a million calories of pork back, but that's why we don't feed pigs broccoli. Still no violation of the second law.

I am not really sure where you think the violation was meant to occur?

Cherry picking some unproductive crops doesn’t prove your argument against animal agriculture’s impact on climate change. Some actually useful real data: http://www.waldeneffect.org/blog/Calories_per_acre_for_vario...

> Cherry picking some unproductive crops doesn’t prove your argument

It was asked by a previous commenter in the thread to cherry-pick a crop that is less efficient than a cherry-picked animal. It was never meant to prove anything, only to helpfully answer the specific question asked. Trying to change the subject now does nothing to help your cause, which nobody really disagrees with in the first place. Even if you come from a heartfelt place, it is troubling that you did not take the time to read the thread before pushing your agenda. That is not the type of community HN strives to be.

Your point about corn being really efficient isn’t exactly well substantiated to be honest. I totally agree about civility, but I think it’s a bit disingenuous to be pointing fingers. Have a good night.

Ah yes that calorie dense food broccoli we all know and love... You need to make the comparison with something like soybeans, oats, potatoes or rice.