It is not that long ago that if you wouldn't use animal products or labour in most of Europe you would starve and/or freeze. Veganism as a lifestyle is utterly dependent on huge energy subsidies.
They love to play tricks with statistics too, comparing the calories in an acre of simple carbs in crops to the calories in the complex proteins in a cow. That's where the energy has "gone"...
> Veganism as a lifestyle is utterly dependent on huge energy subsidies.
What? You are confusing technological development with energy. People used to rely on burning wood for heat also but do you think this is energy efficient? Do you really think that a horse is more efficient for labour than machinery?
In the past people used these inefficient methods because that was the best technology they had available. There is no way we could sustain our current world population if we all attempted to return to their lifestyles.
Yes but you can't discount that. Another example: cycling is only a viable means of transport because of the extensive road network built for (and by!) oil-powered vehicles.
Dried soybeans are 36% protein by weight. Muscle beef is 32% protein by weight, although other parts of the cow are lower in protein. A steer is 4% of the soybeans it's fed, by weight. So feeding soybeans to cattle is even less defensible as a way of providing protein to people than as a way of providing calories to people: you waste 96.5% of the protein that way.
The picture is a little less egregiously bad if you look at some other foods (sweet corn is only 3.2% protein, so if you could get your cattle to grow on corn without supplementing their diet with soy or other protein, you'd only be wasting 60% of the protein). But it still isn't good.
The fundamental constraint here is that animals can't produce protein from carbohydrates or fat. Animals can only produce protein from protein. In fact, most plants can't produce protein from carbohydrates or fat or carbon dioxide or water, either. They need to take up nitrogen compounds from the soil to make protein. As far as we know, animals can't aminate carbohydrates using other sources of nitrogen, the way plants can. So the protein that comes from your crops is the most protein you can possibly get. Processing it through animals can only reduce the protein yield per acre of crops.
The complexity of the proteins in the cow isn't an advantage, either. You have to break those proteins down to individual amino acids before your ribosomes can use them to build proteins of your own. If foreign peptides (protein fragments) get into your bloodstream, your immune system will destroy them. From the standpoint of nutrition, the less complex the proteins are, the better.
On the other hand, animal processing can make the protein and calories considerably easier to eat. Ruminants' symbiotic bacteria can extract useful calories (and massive amounts of methane) from cellulose, even if they only pass 5% of them on to their predators; your body doesn't support these bacteria at all. And cows have these massive jaws and teeth for grinding up cellulosic material to extract the nutrients from it.
So, veganism as a diet (I'm not sure what you mean by "as a lifestyle"} isn't dependent on "huge energy subsidies". It's just dependent on crops you can stand to eat and that provide you adequate nutrition. Eating animals is a huge cost to your primary productivity; the compensating advantage is that it renders you more adaptable in your crops. Eating animal products is somewhat less of a huge cost.
As for freezing, it's fairly unusual for people to heat their homes by burning animals, and in Europe, it was unusual for people to insulate their homes with animals or animal products. Not freezing is really more a matter of thermodynamic engineering than it is a matter of acquiring adequate energy. A good thick thatch roof, a couple of meters of straw bales in the walls, and some whitewash on the inside will allow you to heat even a largish habitation with a small fire. No huge energy subsidies required. (Please don't start complaining about the embodied energy of the whitewash.)
The soy that vegans use to replace animal fats and proteins is horrendously grown here in the US. Most of our soybean crop is of a monocropped, GMO variety using heavy amounts of pesticides and fertilizers. See the recent articles on dead zones in the oceans due to excess nitrogen.
To insinuate that a vegan diet is better for the planet than meat is insincere. In the end it's probably a wash, for various reasons.
98% of the US soybean crop is used to feed livestock, according to Britannica http://www.britannica.com/EBchecked/topic/557184/soybean . Eating the soybeans directly, instead of converting most of them to animal manure, uses dramatically less pesticide and fertilizer.
I request that you withdraw your accusation of insincerity and substantiate your extraordinary claim that "it's probably a wash, for various reasons".
They love to play tricks with statistics too, comparing the calories in an acre of simple carbs in crops to the calories in the complex proteins in a cow. That's where the energy has "gone"...