Farming also have a negative environmental effect and is not indefinite sustainable. It is generally less harmful than beef, but that don't make it sustainable.
The only sustainable diet is one where the total has a environment zero or even positive effect. Honey would be one such animal product, since the work that the bees does has a net positive effect on the environment. Meat from over populations would also have a net positive effect, and is part of the bigger picture when farms use fertilizers and cause eutrophication.
In order for a biological system to remain diverse and productive indefinitely (the definition of sustainability), we need to look at the whole picture. Animal proteins is part of that chain, but a sustainable diet would look very different from a regular meat rich diet. The species, the amount, and also the plants would all have to be very different.
The only sustainable diet is one where the total has a environment zero or even positive effect. Honey would be one such animal product, since the work that the bees does has a net positive effect on the environment. Meat from over populations would also have a net positive effect, and is part of the bigger picture when farms use fertilizers and cause eutrophication.
In order for a biological system to remain diverse and productive indefinitely (the definition of sustainability), we need to look at the whole picture. Animal proteins is part of that chain, but a sustainable diet would look very different from a regular meat rich diet. The species, the amount, and also the plants would all have to be very different.