I just finished a couple of interesting books. First up--The End of Food by Thomas Pawlick. It was first published about 6 years ago and I heard or read much of the information in dribbs and drabbs over the years. However, the first couple of chapters were totally new to me and a bit surprising. After a charming introductory chapter recounting his frustrating experiences with 'red tennis balls' (a.k.a. tomatoes) Pawlick decided to do some research. I knew that over the years breeders had selected tomatoes for certain traits--uniformity of size and color, thick walls that resist bruising so they can be mechanically harvested and easily shipped, synchronous ripening. I also knew from experience that few varieties commercial growers produce as tasteless as tennis balls. What I didn't know was that in the process of developing those few varieties much of the nutritional value of the tomatoes has been lost. According to USDA test results, since 1963, the levels of all nutrients except 2 have declined dramatically, some as much as 60%. The two that have actually increased--lipids and salt. Pawlick also discussed the situation with potatoes which mirrors the results from the tomato tests. He did not mention the calorie value for the vegetables but I rather doubt that those have declined. From there it isn't a great leap to conclude that we have to eat more veggies to get the nutrients we need and that therefore we would have to consume more calories to get those nutrients and that the more calories we eat the fatter we get.
The second book was Empires of Food by Evan Fraser and Andrew Rimas. The authors main conclusion is simple and very common sensical--civilizations grow with their food supply and when that supply is interrupted the civilizations die. But like so many other matters of common sense, that fact is very easily ignored. Why, you might ask? Because of four widely held assumptions. We assume that the earth is fertile. We assume that the weather will be moderate. We assume that specialization is always a good thing. And we assume that the needed energy to produce food will always be there. But these assumptions have broken down before. Whenever anyone thinks about the 'fall of the Roman Empire' they usually think of political chaos, crippling taxes, an out of control military, barbarian invasions or religious strife. We don't think about a climate shift from warm and moist to cold and wet. Nor do we think of soil erosion and exhaustion. Nor do we think of what happens when a region that specializes in cash crops for export can no longer import food. But that was exactly what was happening at the same time that the military was marauding through the country side, emperors were rising and falling with the seasons, barbarians threatened, and a fiscally strapped government imposed crippling taxes. I hadn't mentioned the last assumption yet because I disagree with part of the author's analysis. They restrict the assumption that the energy to produce the food to our modern fossil fuel based agricultural system. And yes we are incredibly dependent on fossil fuels but energy dependence is not a modern phenomenon. Roman Agriculture depended, largely, on muscle power--human and animal. Food shortages result in malnutrition. Malnourished people and animals can't work as long or hard which means they produce less of anything, including food. Malnourished people are more susceptible to disease and during the second, third and fourth centuries the Roman empire experienced several epidemics which seriously reduced the population. The Romans experienced their own 'energy crisis.' I will leave it to you to draw you own conclusions about where our own 'food empire' is headed.