I think this is a more important point that is always missed in free market debates. You need not only perfect information, but also unlimited computation power and skill to compute necessary information. If you can get a CSV file of global potato and onion producers with transportation cost, but you have no means of solving this TSP problem, you will not make an optimal decision.
In particular, relevant to this thread, if you have a magical CSV file created by an Oracle associating every food available in US with how "healthy" they are and how much calory they provide, in order to build a 2500 calory diet that maximizes health and minimizes cost, you need to solve a knapsack-like problem. In this environment market will necessarily be a little random not because we don't have enough information but because we don't have enough computational power.
This is generally the argument against command economies, in _favor_ of market economies. It's formally referred to as the Economic Calculation Problem.
I wasn't making a point against/in favor of free market nor was I suggesting this was a hidden factor I just unraveled. I just don't see this discussed in free market debates, here or in reddit but I think this is a very practical problem for some markets. I personally try to take as much rational decisions as possible and one of the limiting factors for me is knowing good enough algorithms to efficiently compute rational decisions. Of course, we don't have perfect information, so that's a problem too.
EDIT: I must also admit that I know absolutely nothing about economics. I'm a regular software engineer.
You're ascribing extremist anarcho-capitalist views to what you call the 'typical "free marketer"'.
This is false; the typical free market advocate understands there is a limited role for government intervention. Basic examples: Police, fire services, military, currency, lighthouses.
I think you have misread my comment. I think the typical free marketer wants that companies can do whatever they want while still protected by the state.
The free market can work very well if various individuals are missing a lot of information. In fact, the free market is the only system known that works so well in situations where every actor is very information-poor. Our economy is far more complex than any person or organization can understand. The information, and decision-making, are distributed.
In contrast, socialism can only work if the central planners have perfect information and no secrets. That's why it hasn't ever worked - information can't be centralized like that; the economy is too complex. So it ends up depending on a central actor to manipulate reality (see China today or any other socialist economy ever and the blatant lies in their economic statistics).
The issue with sugary drinks isn't that people lack information. The information is written on the side of every soda can; it is nearly a perfect-information situation. The issue is that people are irrational in other ways (related to time preference and inability to moderate impulses or re-evaluate habits).
It's not a perfect information situation. Industry puts out an enourmous amount of misinformation and people who don't do a lot of research can easily be confused (which is the goal). I still remember how long the tobacco industry successfully fought the consensus that smoking is harmful.
