The basic argument of the book is that the current emphasis in ethical eating on consuming "locally grown" food is wasteful, inefficient, unsustainable from both an environmental and population perspective, and ultimately a blind alley. (For example, he points out that transportation consumes a measly 11% of all energy consumed in the 'life cycle' of food; home preparation consumes 25%!! Switching to more fuel-efficient methods of cooking would be a much more sound way to make a positive environmental impact.)
To eat in an ethical manner, McWilliams instead recommends the following (backed up by excellent, well-researched evidence):
- Don't worry about buying local; instead, buy crops from the region naturally most suited to grow them, even if that's thousands of miles away. In other words, the division of labor should be applied to the growing of food as well. Some locations will have to ship all of their food from elsewhere (like Tucson or Las Vegas); most will have to ship a large portion of their diet (like New York, which can only produce apples in sufficient quantities to feed its population).
- Organic food is not that great. Thanks to inconsistent and deliberately vague regulation and enforcement, the designation "organic" does not necessarily mean anything meaningful. More importantly, even truly organic food does not solve the problems it purports to: organic food tends to consume more resources, not fewer; still uses extremely toxic and dangerous chemicals (albeit naturally derived); is not environmentally sustainable; and may actually be worse for the soil and natural environment.
- Genetically modified crops are a wonderful solution to many problems, such as world hunger and malnutrition, the overuse of pesticides, and the destruction of the natural environment for cropland. We should encourage their use (and the development of new ones) whenever possible.
- Eating meat is not environmentally sustainable and should be avoided, or at least only consumed on rare occasions. Factory farming is worst, but this is true even for grass-fed, free-range animals.
- Freshwater fish farming, while not currently perfect, is a wonderful solution for producing protein for a growing population. He speaks especially highly of tilapia and catfish.
- Agricultural subsidies and protectionism are wreaking havoc on both the environment and our food systems, and need to be eliminated. Greatly enhanced global trade of food should become the norm (see point #1).
There were a few things I didn't like.
--McWilliams is an academic, which means (unlike, for example, Michael Pollan) he isn't much of a prose stylist. While the book is perfectly readable, it's a little bit repetitive and dry.
--McWilliams is very concerned with the ethics of food (what the 'just' in the title refers to). However, this very concern means he overlooks the main function of food: its taste. Tilapia and catfish in my experience are rather disgusting, which is going to be a major barrier in their widespread adoption. Similarly, a major reason to eat local produce is because it tastes much better (by a HUGE margin). McWilliams completely ignores these and all similar issues.
Overall though, I wish everyone would read this book and become a convert. I think it would make the world a better place; I will be doing my best to do the same myself.