The problem with moderation is that the word itself carries no meaning. What you are basically saying is the SAD is okay. And it probably is for the most part. Longevity and health have very strong genetic components...
Nope. I don't think anyone is saying the Standard American Diet (SAD) is okay. I can't speak for other cultures, but Americans are categorically and willfully ignorant when it comes to select sciences: health, climate, economics, biology, etc ... A huge swath of our population actively denies basic realities that the rest of the world have already adopted: even though we're told otherwise by authorities and governing bodies.
The FDA, an agency of the US Government, as well as many other organizations, have actually put together a fairly decent guide for individual and family nutrition, and they are constantly updating it as new data becomes available. The problem: too many people are too stupid, selfish, ignorant, or all of the above to follow such simple suggestions, hence the SAD. It's self-inflicted ridiculousness.
Paleo diets are a bit of a myth given that all our modern food no longer resembles what it was, but modern food is overly weighted to sugars/carbs so anything that counteracts this is mostly good.
The first part of what you said is absolutely true.
Paleo is a myth? So like if you went back 100,000 years a Wild Salmon would look different? mmmkay.
Paleo is pricy - but not a myth. We know what foods existed back then - and we still have the same foods available today. They just cost alot.
Anybody who suggest you should live like Paleolithic Man is utterly, and ridiculous, and willfully ignorant. What's much more likely, is that they're just straight up lying to you.
The Paleolithic Age of human history is not a myth.
The Paleo Diet is a brand name, bearing virtually zero resemblance to the actual paleolithic age. People who think they're following their ancestors diets have been hoodwinked beyond imagination. The Paleo Diet's claim to "your ancestors" is absolutely a myth. Here's why:
The Paleolithic Age extends from as far back as 2,600,000 years ago, to about 10,000 years ago.
It's prehistoric. We're talking about a time when homosapiens didn't even exist. It was a time for millions of years that our distant, distant ancestors--the Hominis, not even yet neanderthals--were just starting to craft tools from
bones and rocks. In the beginning of this era, the homonis didn't even have control of fire yet. Fire, guys. Fire had not been "discovered" yet. The very earliest, somewhat fringe claims of fire control is about 1.7 millions years ago. Homoerectus started getting this practice down about 400,000 years ago.
The animals you see, the plants that you see, the food that you eat today bears virtually zero resemblance to anything that existed in the Paleolithic age. Over the course of the last ten thousands years, farming and husbandry has been genetically altering the food and plant supply we use for food through selective breeding, and grafting.
So, which period of time is your Paleo diet from? Where you not even human yet? Is it from 2.6 million years ago? 1 million? 500,000? 150,000? 10k? Which one is it?
This argument is so ridiculous.
Unless you're bashing raw pieces of meat with rocks and bones and trying to eat them, you're fooling yourself into thinking you're "eating like our ancestors." And that piece of meat you're buying at the supermarket did not exist back then. Where exactly are you getting your prehistoric meat and vegetables from? The vegetables you're eating now did not exist. And even if you say, "fine, I'm following the 10,000 year old diet," you'd still have virtually no idea what you're talking about, nor would it even be possible. The effing wheel hadn't even been invented yet!
Hahahahahahaha. 
