Nutrition professor Marion Nestle argues that we should lower our salt intake, and that studies showing no correlation between high salt intake and poor health outcomes only fail to do so because finding a low-salt-intake control group is now almost impossible.

For her, the two main culprits are processed food and restaurant food.

The latter isn't surprising; in culinary school one of the cardinal sins they hammer into your head is to never send out a dish that is under-salted. Salt enhances flavors of a dish. At a poor low-end restaurant, most dishes tend to be too bland or under-salted. At a higher end restaurant, it's more often the case that a dish comes out over-salted because the chefs there err on the high side.

That's the problem contemplated in this article in The Atlantic. That's one way to look at the problem, to back out from some predicted future population figure and then solve for that equation.

The author's conclusion is that biotech won't solve the issue, that the only way it's possible is if we (1) raise incomes the world over (because some people aren't fed today purely because of poverty, not because of a lack of food supply) and (2) convince people to eat less resource-intensive food, of which meat is a large culprit (the higher up on the food chain you are, the more resource-intense you are as a food source, which is why we couldn't feed many people at all if we just fed them lion meat).

Here's a long and related article in the NYTimes: Beyond the Eternal Food Fight.