Salt (and a rant about water)
Sodium intake will naturally drop significantly when you eliminate processed foods. I consume far less salt than I used to and have become very sensitive to the taste of it. However, after a period of cutting it out completely I have reintroduced adding salt to my cooking for two main reasons: firstly iodized salt is a good source of iodine - vital for thyroid function and deficient in many strict Paleo-ers who eschew salt. And secondly, salt really does enhance flavor.
As a side note, the concerns of sodium contributing to hypertension seem to be largely overstated (Chris Kresser mentioned this on a recent podcast).
Furthermore, this whole idea of having to drink 2-3 litres of water everyday in addition to that consumed through food and drink is so overprescribed and token these days that I think it is a moot point.
I am a particularly sweaty guy, as many of you who know me could vouch for. Yep, I am the gross guy dripping sweat from the nose after five minutes of Vinyasa yoga. So yes, I drink a ton of water when I need it. However, if it is winter and you are sedentary and drinking tea all day long there is no way in hell you need to add 3 litres of water as well (unless you really enjoy going to the restroom as frequently as possible). Let thirst guide you.
I'd hazard a guess that most hunter-gatherer tribes would not be carrying around gallon-size vessels of water during their hunting or gathering sessions. It just doesn't make sense. The human body is incredibly efficient at maintaining hydration given ADEQUATE water, which you can largely get through eating whole foods. No need to overdo it. Yes drink water, even more than you need, just don't get neurotic about it.
Drinking water during a meal is not a great idea either as this dilutes stomach acid, which is already low in many people and can lead to significant digestive issues in such individuals. Not to mention the fact that bottled water is a scam and a massive environmental issue today.
Butter (and a rant about evolution)
OK, yes I get it. Cave men did not go and try to milk a wild bison. That would be about as silly as cow-pushing and a lot more dangerous.
Let me get something straight: just because our Paleolithic ancestors did not consume something does not necessarily mean it is bad for us today.
It would be completely ignorant to assume that it is not possible to find new sources of nutritious food. We would not exist today had we not been able to discover (and thrive on) new sources of food. Need I remind you a few million years ago we used to eat bark, twigs and leaves and have big distended guts (to digest this nutrient poor organic matter) until we started scavenging meat scraps (marrow, brains). As evolution dictates our brains grew in size while our guts shrank in line with our ability to hunt (and then cook) other animals.
Now after that deviation I can get back to my original point. Dairy is potentially THE biggest grey-area in Paleo. However, GRASS-FED butter it is increasingly becoming accepted as a nutrient-dense and relatively benign or even healthful option. As butter is almost pure fat, it contains no lactose (sugar) and virtually no casein or whey (protein). For this reason almost everyone can tolerate butter, and most can tolerate heavy cream.
I love butter and use it for cooking and even in my coffee! (I will write an article on "Bulletproof Coffee" another time). Furthermore, heavy cream and even fermented dairy products such as kefir or even Greek-style yoghurt and hard cheeses are probably not as harmful as many Paleo folk would have you believe, especially if made from raw milk from pastured cows. I include things like goat's cheese, Parmesan and sour cream in my diet ON OCCASION for some variety. I DO NOT eat these things every day.
I would definitely recommend people cut dairy completely when they first begin Paleo for at least 30 days (ala Robb Wolf's 'The Paleo Solution' - best book on Paleo in my opinion - or the 'Whole30 challenge').
After 30 days you can slowly reintroduce some dairy products, starting with the least allergenic/problematic and working down from there and see how you feel. (e.g. Ghee, then butter, then heavy cream, then sour cream, then hard cheese, then yoghurt).
If you are trying to lean out then it is probably a good idea to stay clear of most dairy until you are happy with your weight. There are potentially some insulinemic (insulin spiking) properties of dairy that may hinder weight loss if consumed frequently.
Milk - the main form of dairy high in lactose - seems to be fairly problematic for most people and I would argue milk is not Paleo at all, especially the crap available these days from ill-treated, sick cows pumped full of hormones and antibiotics. Finally let me reiterate that I have emphasized GRASS-FED dairy, preferably from pastured, organic cows. Grain-fed dairy is a completely different beast all together and it is safe to say that it is no good.
PS - I understand that veganism and vegetarianism are at odds with the Paleo diet. I do support those with legitimate reasons to be vegan or vegetarian.
However, from a health perspective, I am convinced that eating at least SOME meat, seafood, eggs and/or other high quality animal products is healthier than not eating them at all.
The problem with veganism/vegetarianism is that you typically need to rely on grains, legumes and soy for nutrition - all of which pose health problems when eaten in quantity. Not to mention the likelihood of other micro-nutrient deficiencies arising from avoiding animal products altogether.
There are no scientific records of any large, successful populations throughout verifiable human history who did not incorporate at least some animal products in their diet.