1. Do we know the quantities of types of foods that Paleo people ate? If not, would this knowledge change the diet recommendations?
One thing we know is that a typical hunter-gatherer tended to eat a few leftovers in the morning, hunt/gather all day, then have a big meal at the end of the day. They were metabolically well-equipped to handle food scarcity / fasting.
[[MORE]]An important aspect of the diet recommendations is that they are based on the metabolic conditions that we evolved under. Since those conditions are only loosely associated with quantity, I think even if we knew more details about exactly how much the Paleo people ate, that it wouldn't significantly affect the recommendations.
2. Humans obviously ate grains (they got the idea to cultivate them after all), but was the quantity just greatly reduced to the post- agriculture quantity? Or perhaps they started eating them just recently before agriculture was developed?
Monocot grass seeds and gluten cereal grains were at best inconsistent and trivial sources of food prior to the advent of agriculture. Also, the fact that a food was available or sometimes used tells us nothing about its long-term impact on health, or whether it's better to eat that food vs. something else.
Unfortunately, cereal grains (and legumes, including peanuts) contain anti-nutrients with clinically significant health effects -- and we are poorly adapted to consuming them.
4. Honey, agave nectar, coconut sugar, stevia, maple syrup....good, bad, same as cane sugar? I don't understand the differences well. From what I've read, people seem to think that while they may be less processed and have a lower GI than cane sugar, they all still have the same addictive properties.
From a health perspective, there are three primary factors to consider with sweeteners: total carb content, and the fraction that's fructose, and whether it's artificial. It turns out that GI or GL are poor indicators. What's more important for long-term health is total insulin produced, rather than the size of the post-meal spike -- and the total is directly correlated to carb content.
Fructose is evil, and I would avoid it as much as you can. It's responsible for conditions like gout; it goes directly to the liver, where it's converted to triglycerides; it drives insulin resistance in the liver. Fructose may be the single biggest cause of a broken metabolism (although gluten is right up there too).
For artificial sweeteners, history says they don't have a good record when it comes to health effects. Also, even though they're artificial, they can still cause insulin to be released. Even brushing your teeth with an artificially sweetened toothpaste can cause an insulin spike.
The sweetener I prefer is glucose, also known as dextrose -- although I only use it in very small amounts.
