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  • Writer's pictureEve Was Right

The Science Behind Kosher Dietary Laws

And why they are definitely not more humane.

Kashrut, or the Jewish laws on Kosher dietary practices, are by far the most numerous and exacting of any religion. Despite the plethora of resources that explain the religious basis for these laws, there are very few sources that provide the scientific underpinning and comprehensive explanation for each rule. 

Until now. (Dunh dunh dunh…)

It took me forever to learn the ins and outs of “keeping kosher,” as it’s called, so I thought I’d compile everything into one handy place. If doing so also happens to demonstrate a deeper truth about humanity, so be it. 

Here we go. 

The laws of Kashrut (kosher) consist of two primary elements. The tranche of laws mentioned in the Torah focuses on categories of forbidden consumption - the types of animals Jews can and cannot eat. The second, which was added later by rabbinical decree, focuses on methods of slaughter. 

All the kosher laws - even the rabbinical ones, which, if you read my previous posts, you know I don’t put much stock into anything the rabbis say - were remarkably advanced for their time. Thousands of years ago, Jews bent over backward to find the most humane method of slaughter available to them. Additionally, many of the rules around permissible and outlawed animals ended up having a surprising amount of scientific backing for laws created thousands of years ago. 


Fast-forward thousands of years, and now we find ourselves in a conundrum. Which of these laws still make sense? To answer that question, let’s dive into the details. 

Anakin Padme meme. The setting: Religion, 4000 years ago. Anakin tells Padme "These laws are brilliant." Padme asks optimistically, "But eventually we'll change them, right?" The truth dawns on her. She tries once more: "We're going to change them, right?"

Laws regarding consumption (clean and unclean animals)

  1. Only eat land animals with split hooves and chew their cud (ruminants.) 

  2. Health-related. Because of their thorough digestive processes, ruminant animals have a lower chance of passing on disease. 

  3. Also, animal welfare related. Because of the way ruminant animals are innervated, they stop feeling pain after a single vein is cut. For non-kosher animals, there are two veins, meaning cutting one will not stop the animal from feeling pain upon slaughter. 

  4. Only eat water animals that have both fins and scales. 

  5. Health-related. Shellfish have simpler digestive processes and thus are more prone to passing disease and toxins onto humans. 

  6. Birds are listed by name, which is inconvenient since we don’t know what the names translate to. However, one thing is clear: no carrion birds. Again, this is health-related.

  7. Don’t eat meat and dairy together. 

  8. The justification for this one is energetic in nature, but unfortunately for my unholy love of cheeseburgers, it does make sense to me. Dairy = mother’s milk = life-giving, and meat is, well, dead, and it’s energetically beneficial to keep the two separate.

Kosher Slaughter

These were rabbinical decrees, which means they were codified after the fact by men. Moses was also a man, but unlike Moses, nobody is claiming God spoke directly to the rabbis who bequeathed the rules for kosher slaughter. 

Because of this, the rules around kosher slaughter offer an excellent glimpse into the minds of humans who lived millennia ago. In spite of all their flaws, the ancient Israelites did their best to find the most humane method of slaughter possible. 

We run into a problem when we try to apply these rules to contemporary life. Science has given us better, more humane ways to raise and slaughter animals. 

Should we continue on the path of kosher slaughter, assuming ancient rules still remain relevant today? Or should we accept the natural evolution of our society and recognize kosher slaughter for what it was - a valiant attempt to forge a better path, a path we’ve continued on with our new science-informed methods? 

Let’s examine the rules themselves before making a decision. 

  1. Kosher slaughter

  2. Health-related reasons

  3. Kosher slaughter mandates the removal of all blood and nerves, plus some organs. Even the kosher-approved organs go through intense cleaning to remove the blood. These processes deliver a lot of health benefits; for example, removing the nerves in cows nearly eliminates the chance of mad cow disease. Thoroughly cleaning offal decreases parasite risk. 

  4. Animal welfare-related reasons

  5. Like everything else in Judaism, kosher slaughter comes with an enormous amount of rules. Today, there’s a big debate going on about whether kosher slaughter can still be considered humane compared to contemporary slaughter methods. Temple Grandin is the world’s foremost authority on animal welfare in slaughter. According to her research, a well-trained kosher slaughter practice causes the animal minimal pain (this is not true for halal slaughter. They are different in ways which are outside the scope of this article.) When it comes to kosher meat production, the method of slaughter is not the issue - the process of restraint is, which I’ll get to in a moment.

I am not naturally inclined to give ancient Jews much credit, but they deserve credit for this. During a time when laws barely considered human welfare, Jews were ritually obsessed with determining the least painful and most humane way for an animal to die. 

The problem is that they kept those laws and refused to evolve. The most horrifying example of this can be found in the stomach-churning “shackle-and-hoist” method of restraint. Before slaughtering an animal, it must first be restrained. More than 60 (Sixty!) years after the practice was outlawed in conventional slaughter in the United States, kosher slaughterhouses used religious exemption clauses to continue practicing the “shackle and hoist” restraint method. 

I’ll speak plainly. Jews used their religion to perpetuate one of the cruelest forms of animal torture known to humankind, decades beyond when the rest of America decided it was too horrible to contemplate. And yet, somehow the propaganda around kosher slaughter remains centered on animal welfare. 

Even I, as someone obsessively concerned with animal welfare, assumed I was doing better by the animal when I chose kosher. Even people who do not keep kosher, when they hear I do, say, “Oh yeah, it’s more humane, right?” 

Propaganda in action. Little did I know that behind this veneer hid a horrible truth. 

Pigs Are Not "Dirty"

I want to tackle one more concept that isn’t found directly in either the Torah or the rabbinical teachings. I call this the “pigs are dirty” concept.

If you have observant Jewish friends, you’ve probably heard them say pigs are “dirty.” The tendency for religious Jews to denigrate some animals just because kosher dietary laws prohibit their consumption is annoying at best and bigoted at worst. It doesn’t help that the only reasoning provided by the Torah was that certain animals were “abominations.” 

Fortunately for you, I’m a complete nerd when it comes to this stuff and love little piggies. Oink oink. There’s a much deeper and more interesting truth hiding behind the special disdain reserved for pigs. 

At first, I didn’t understand why, of all the animals, pigs got the bad rap. Poor buddies. Millennia ago, I could kind of understand it; pigs eat everything, which means they ingested lots of toxic stuff and passed it on to humans. But today?! The only reason pigs are “dirty” today and eat slop is because we feed them slop. 

If you feed a cow slop, all hell breaks loose, and they get all kinds of diseases. In other words, our mistreatment of cows is obvious. Pigs, on the other hand, can absorb a lot of damage before showing it. They can eat slop and still come out okay. We can hide their mistreatment. 

Their behavior tells the truth. “Pigs eat their poop,” you might say. Yes. Just like dogs do. But dogs eat their poop as a manifestation of a psychological problem. 

If your dog eats its poop, I have news for you: your little buddy is anxious. Maybe they’re bored, maybe they don’t exercise enough, maybe they have separation anxiety. No matter the cause, I guarantee you, your dog eats their poop because something is wrong. Same with pigs. 

“Pigs eat other pigs,” you might reply. Again, the same with dogs. But do they do it as a rule? No. They do it if there’s no other choice and if their environment doesn’t give them better options. 

Pigs are more sensitive than cows. They die from grief if they’re rehomed, and they’re extremely intelligent. Perhaps they offer a litmus test for our morality. Do we feed them slop and rush them to slaughter? Do we keep them in unclean environments and allow them to succumb to their worst instincts? 

Or do we elevate them? Do we give them the life they deserve? Do we feed them good food, keep their pens clean, and shower them with love? 

What separates them from cows then? Nothing. 

Pigs aren’t dirty. They just reflect our society’s flaws back onto us in a clearer way than most other animals we eat. 

After much exploration, I decided to give up kosher eating. I had already transitioned to a fully pasture-raised, grass-fed kosher meat provider. Now, though, after extensive research, I’ve parted ways with kosher slaughter, because we’ve come up with better things. Go us!


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