Is a Kosher diet a healthier lifestyle or is it really just a mitzvah?
Yes and No.
What these laws did was it effectively standardized the Jewish diet. It made sure that our food was prepared safely and it made sure that contamination of food was low.
1) Separating meat and dairy cuts down on food contamination.
By creating separate storage situations for both meat and dairy, we would never have a situation where ALL of the food went bad. If the meat went bad then we would still have the dairy and vice versa.
Not eating meat and dairy together also cut down on food poisoning. If I eat meat and I'm forced to wait a few hours before I can eat dairy (as to keep it separate from inside my body) then this means I'm not mixing two types of food.
2) Kosher slaughter ensures that meat is "pure."
Kosher Slaughter involves bleeding out the animal before we process it. Most disease is spread through the blood. The flesh inside of the body is sterile for the most part. By separating the blood from the flesh, we ensure the purity of the meat by making sure it will not be tainted.
3) Certain types of Shellfish contain toxins which can kill you or harm you.
The blanket ban on Shellfish ensures that we are never putting ourselves at risk of poisoning. Certain types of shellfish contain toxins which can either harm you or even kill you. Today we can differentiate which shellfish is dangerous and which is safe but we still honor the laws because they were as they were given.
4) Eating animals which only chew their cud ensures we aren't eating the flesh of animals which have inefficient digestive (purification) systems.
Animals which chew their cud have extremely efficient digestive systems. They break down their food efficiently and they do it slowly over a long period of time. This means they have the ability to purify their bodies of toxic materials in a more efficient way.
- The digestive system of the pig is extremely short (around four hours) and doesn't remove toxic materials efficiently. A cow takes about 24 hours to fully digest food which allows it to fully purify materials from its body. This means the meat and fat aren't storing toxic crud we shouldn't be eating.
- Pigs lack a number of sweat glands which other animals have. Sweat glands are part of the purification system of the body. This means pork holds a higher amount of waste material.