He's more than a touch over the top, but people do have some very weird notions about nutrition too, as though it weren't simply a checklist of micronutrients available from any number of sources. Still, there is serious resources usage involved in transportation and storage of foods from further off. For some, like grain, such concerns are risible, it takes less resources to move and store an entire ton of grain then to go pick up a sack of flour from the store, but for produce it really would behoove us to grow that more locally, which means preference diet to those plants more suited to grow locally.

Where it goes over the top is forgetting that just because bananas don't grow in Massachusetts naturally doesn't mean people shouldn't eat them, nor that they can't be grown locally via greenhouses. Hydroponic lettuce is cheap to grow anywhere with new techniques, and that should be encouraged where economically reasonable over importing it from another hemisphere, but we definitely are better with either option then simple going without salads all winter long. Cutting down supply lines and associated expenditures isn't nutty, it just can be when taken over the top.