There are sustainable fisheries. For example:

http://www.theecologist.org/how_to_make_a_difference/food_an...

And interestingly enough - the fish in Macdonalds fillet of fish is sustainably produced as well.

Again I can't recommend the book "end of the line" enough (as I notice others have on this page. Including me ;-) )

Our ancestrors did not eat meat or fish every day, today's vegetarians do not eat tofu everyday either. The goal is to be complete in nutrients: you won't be much wrong if you associate cereals, legumes, fresh vegetables, fruits/dried fruits (to get glucids, fibers, proteins, vitamins and minerals) and possibly some dairy products/eggs for lacking nutrients. Think of the traditionnal associations (rice and beans, couscous, houmous and bread, fallafels and pitta ...) and try to be diverse and curious. Cooking is a form of hacking !

Who were your ancestors? How far back are you talking about? Hunter-gatherers? I think you'll find that people ate pretty much everything edible around and that meat was a highly desirable food and eaten whenever possible.

You're right - meat was highly desirable food and eaten whenever possible, HOWEVER - up until the 19th century, unless you were in the very small percentage of rich/privileged, you got a chance to eat meat once a week - tops. And in the agricultural societies, commoners wouldn't even get to eat steak and all the nice parts - when a cow was slaughtered, all the premium parts went to the lord.. all peasants got was some entrails to put in soup.

It's only when the 20th century rolled around, and meat became cheap/available everywhere, that people started eating meat once a day, leading to a spread of all kinds of diseases, heart attacks, cholesterol, cancer, etc.

> you got a chance to eat meat once a week

Really? Is that true? What groups are you talking about?

> It's only when the 20th century rolled around, and meat became cheap/available everywhere, that people started eating meat once a day, leading to a spread of all kinds of diseases, heart attacks, cholesterol, cancer, etc.

Ok, interesting hypothesis. So assuming this is true, people in 1830 ate less meat and had less heart disease than people in 1930, right?

What if I told you, in the US, the opposite is true? That, on average, people ate more meat in 1830 and had less heart disease than people in 1930?

If people aren't eating meat, what are they eating? grains? sugars? How would you create a study to test your hypothesis than meat consumption causes heart disease? Has this been studied? What were the results?

What if I told you, in the US, the opposite is true? That, on average, people ate more meat in 1830 Then I would ask you what your sources are.

If people aren't eating meat, what are they eating? grains? sugars? Vegetables, fruits, legumes, whole grains, nuts, etc. Most people in the US who eat tons of sugar are not vegetarians.

> Most people in the US who eat tons of sugar are not vegetarians.

How do you know this? Have you studied the sugar consumption of vegetarians?

Since most people eat too much sugar (the average American eats 20 teaspoons of added sugar each day), and only about 5% of the population is vegetarian this seems common sense to me.

> It's only when the 20th century rolled around, and meat became cheap/available everywhere, that people started eating meat once a day, leading to a spread of all kinds of diseases, heart attacks, cholesterol, cancer, etc.

It's not that simple. The Inuit are an obvious counterexample. In fact, if you look at many hunter gatherer societies (Ache, Yanomamo, Waorani, !Kung, etc), almost all eat some form of meat (I'm including arthropods as meat) almost every day.

Cancer, heart disease and other afflictions that appear later in life are probably more common in the 20th century largely because life expectancy is so much longer than it used to be, not because of regular meat eating.

This is a distorted view of history. Western societies in 1800 were among some of the sickliest and weakest that history has ever known, as population pressure was very high relative to available technology. Death in childbirth and childhood were both very common, and people from the Middle Ages enjoyed better health when using measures of average height. I've read speculation that the British Empire gained its edge because its people were able to get a small dietary advantage.

So we should not look at pre-industrial tradition for information on ideal nutrition. Those people were doing everything they could to survive, and they barely succeeded.

Just go back 50/100 years ago before the food industry. I mean in my previous comment I'm taking as example traditionnal dishes which where already quite complete even when people couldn't afford meat/fish at every meal.

You should start by questioning what health benefits people say you are getting. For example, you may not need omega-3 from fish if you reduce other sources of omega-6 in your diet. You should also question anyone that tells you to substitute beans for fish or any vegetable for an animal- the nutrient (and anti-nutrient) composition is going to be entirely different. Fish is generally a good source of vitamin D and iodine in addition to the nutrients of land animals. You can get iodine from seaweed. Eating more than small quantities of properly prepared tofu is making yourself a human experiment. Pasture raised meat is sustainable and healthy. Hopefully we can figure out some sources of sustainable seafood!

You would be amazed how easy, enjoyable, cheap, and healthy lentils, peas, and a variety of other beans are for replacing meat.