It doesn't seem that most people are willing to give up meat/certain animal products.

Maybe if they had to pay for the externalities.

Tech and transportation better be paying too then. How much pollution you think those Chinese factories pump out to make your $1000 iPhone?

While not giving up entirely, I feel like many people, if presented with facts, would be willing to greatly reduce their consumption.

oh the naïveté of youth...

The easiest way to reduce meat/fish consumption is to make the cost reflect all the externalities.

Then also make the airlines price seats to pay for externalities. I bet people won't be flying as much if the seat cost $5000 instead of $500 to pay for damage to environment. Don't single out ag. Tech and transportation are just as bad. At least with agriculture, it produces food.

So, I agree with this in theory, but how does this work in practice? To stick with the topic of seafood, it's just out there in the ocean; as long as it exists in fish-able quantities, people will fish and fish until there's none left. Pricing in externalities would be huge for the US, but it would need to happen on a global scale to make a difference.

> if presented with facts, would be willing to...

Now that is SF

No, it is not. People just choose not to see the facts. People do not want to know where their food comes from as they suspect it would be not good to know as changing habits is hard and they have lots of other stuff going on to take care of.

But once they have seen movies like "we feed the world" they do care at least a bit.

No, the answer you'll get has an 85% chance of being, to the word, "Oh, I don't think I could ever give up bacon." I know that answer might seem a little far-fetched, but it will happen time and time again.

Facts don't really change anything when they're easy to ignore.

I'm a year into a daily vegan diet and haven't noticed this. When will my GI tract collapse?

Start with vegetarianism (with B12 supplements only). No cheat needed, plus you'll be in your best form.

Now, there are people sensitive to a certain kind of insoluble fibre, and if you are you might have some trouble on a vegan diet, but these people are in a minority. Apart from people wanting to avoid FODMAPs (the fibre group in question), the only problem I have heard of from friends becoming vegan is the transitory flatulence from eating beans.

Anecdotally the worst gastrointestinal problems I have ever had was on whatever version of the standard American diet I was served when visiting the states as a 20-something year old. I couldn't shit for 10 days...