I've been thinking mostly about actual paleolithic children rather than modern-day equivalents. I imagine they got a decent supply of breastmilk, but can't imagine they then started in on pureed vegetables - whatever your stance on carbs is. What ideas or evidence do we have for how children used to eat?
I can well see that an addiction to sweet food, breads and cereals, and general fussy eating can easily be produced in a world where these things are available and permissible. Did they just start nibbling leaves? I can't see how that would be a great step forward for development over milk. Surely they must have been getting involved with the animals sooner or later. Were they tearing into juicy bits of liver (for a good ol' vit A overdose)? Did they subsist on sucking the blood out of bits of meat? Did they just breastfeed until they had the teeth to tackle the meat directly? Are the rules basically the same as for adults? Make the right foods available and let them figure it out? I'm sure we must have some idea what the historical situation was, but how does it fit with the science, and what do you do in a world where you can't hope to stop other people feeding your child foods which might set off a life-long dysfunction?
I can tell you what we did with my last child. When he was about 4 months old, he began to show active interest in my food, which was almost without exception meat on a bone with juice on the plate, or perhaps broth with chunks of meat. I started feeding him some of the juice or broth on a spoon, which he obviously really enjoyed. Soon after that, I would let a tiny piece of boiled meat get on to the broth spoon. When he liked that, I started chewing meat for him. Finally, I started letting him chew on the bones, and gradually started leaving more meat on them before handing them over.
Here he is at 6.5 months in a typical pose:
I'm sure it depends what part of the world / what tribe we're talking about here. Different cultures had different foods. I imagine the toddlers would eat whatever the parents are eating.
Have you seen this link?
First foods should be nutrient-dense. Grains tend to be difficult to digest for small digestive tracts – so avoid introducing them until your child is at least 18 months old. Iron-fortified cereal is not necessary first food (learn more about iron deficiency in the breastfed baby). The Weston A Price Foundation recommends a mixture of liver and egg yolk as a good first food which is very dense in nutrients. Oceanic tribes typically started babies on liver, fish and grubs. Polynesians started babies on breadfruit and coconut cream. Japanese mothers traditionally started their babies on a thin gruel of milled rice, fish, fish roe and mashed pumpkin. In Latin America, traditional foods often include liver and well-cooked chayote in broth. In western societies, first foods often include liver, roasted bone marrow and soft cooked egg yolks. In some cultures, mothers prechew foods into a fine pulp before feeding babies. The take away is that all societies fed their babies nutrient-dense traditional foods, and what the parents also consumed.
In the movie Babies, I saw still-breastfeeding toddlers find their own insects, and eat mashed tubers (I think it was taro root?). I think it munched on bone for a while too, can't remember for sure.
http://www.amazon.com/Babies-Thomas-Balmes/dp/B002ZG974M Good movie, don't dismiss it because it has no narrative. :)
I assume you know that we can't know for sure, no one can tell you unless they've seen it personally...
In my mind I can see small children sucking and chewing on bones. And there is a chance that the parents pre-chewed foods to present to their young until they got teeth of their own.
The other issue you bring up about lack of control over what modern day kids may eat is a whole other problem. I think all you can do is make sure they are fed well at home with Paleo foods and they will be so satisfied they will eat less of what others offer them when they are out.
Probably the most you can shoot for is that they will be 80% Paleo and 20% SAD unless you live in isolation.
A family friend of ours used to chew food into a pulp and feed it to her baby. Not attractive, but effective.
I can imagine that this may have been a used method to introduce solids, and perhaps provide immune support.
I think the natural next step when an ancestral baby would show interest in solids would be to share well chewed foods from the parents' mouths...their saliva would begin the digestion of foods to make the transition easier on a baby with maybe one or two teeth (the initial onset of teeth signals that the digestive system is beginning to be mature enough for the introduction of solids)...I have no idea if there is proof of this, but it seems so obvious to me that this is the natural progression, and this is what I intuitively did with both of my babies.