I thought 2% fat milk was the most unprocessed milk, as it comes from the cow with the cream scraped off, and full fat, which is about 4% fat, was processed to incorporate the fat? If that's the case, low fat isn't really a by product.

We kind of drink whatever is around. It's not a big part of our diet so I don't think it makes a big difference for us. ( I won't buy 'diet' anything though, mainly due to the chemicals and artificial sweeteners. )