One thing I've noticed more and more often (perhaps as I transition to a curmugeon in my advancing years...) is the zealot-like passion with which causes are adopted by people.
Vegetarianism and veganism in the Western world are two such examples.
In other parts of the world, a vegetarian or even vegan diet may just be due to environmental factors coupled with religious reasons. And the people practicing such could be regarded as healthy overall.
Now, when such a dietary restriction comes to the West, suddenly, it's taken up with religious fervour denouncing all else. Eating organic, locavores, etc - all are guilty of this.
I understand why it's a reaction to the commercial meat/fishing industry (since they have much to answer for - and fix), but the extent of the blame and shame reaction is what makes me shake my head in dismay each time. For hyperbole's sake, they make Islamic terrorism appear like a children's scuffle in a sandbox, almost...
The key would be, in my thinking, having a balanced dietary intake - so not a single food stack (or pyramid), but multiple different variants each with their list of types of nutrients (protein, carbohydrates, fiber, etc) showing which dietary lifestyle has more or less - ideally coupled with long-term health risks for each.
One cannot force humans to stop eating one particular kind of food - short of making it economically prohibitive. Something no government in the world should do - as that's overstepping boundaries.
Those animals that are farmed will not go extinct - and I applaud efforts being made in fisheries - to be able to restock and replenish while still providing a source for food.
All this food thought is making me hungry as it's lunch time...