It is a collection of knowledge that was passed down for generations verbally until finally written down. Some parts may be historical, some parts might be parables to make a point and others were laws of the culture.
I believe some of the restrictions had more to do with public health, like eating of pork and shellfish. Sanitation at the time was not very effective and pigs, while eaten around the world are dangerous to eat if not raised and cooked properly. Plus add in the waste getting into the water supply that the shellfish they could reach. Shellfish at the time was probably full of nasty run off.
The same can be said of the Muslim belief of not shaving. When it was written into the Koran any small cut could be deadly if it got infected.
But I have some issue with it due to the Council of Nicaea. They decided which books made it into the Bible and which didn't. They deemed the other books hearsay because it didn't fit their vision. For me that was a deal breaker.