Eating from sustainable food sources doesn’t have to be an all-or-nothing decision.
It seems to me that people often think of vegetarianism in black and white. You either eat meat or you don’t. Same for veganism: you either eat animal products or you don’t. Hank Green of the Vlogbrothers often talks about “going veg” as an event. But from an environmental perspective, this just doesn’t make sense.
The atmosphere doesn’t care whether one person cuts out beef completely, or whether two people cut their beef consumption in half. Every bit helps, even something as simple as observing meatless Monday or buying soy milk instead of cow milk. I describe myself as “vegetarian” most of the time, but I sometimes buy tuna sandwiches at Subway.
I suspect the tendency to black-and-white thinking stems from moralistic arguments about vegetarianism. If eating animals is “bad,” then a meat-eater has no incentive to reduce their consumption of meat unless they completely eliminate it—which is such an enormous step that of course nobody takes it. Instead, let’s talk about reducetarianism. Try to substitute protein from plant sources in whatever way seems best to you. It’s okay, you don’t have to give up bacon!