That's a lot of rabbits

It would seem, according to this article, that a lot of American backyards could raise a lot of protein for the household: 

People eat a lot of protein in the U.S. and the average person needs 51 grams of protein every day, according to the National Institutes of Health (NIH) Dietary Reference Intakes (DRI). That comes to 18,615 grams each year or, for an average household of 2.6 people, 48,399 grams per year. Americans love burgers, but few people have room to raise a steer next to the garage -- and most city ordinances quake at the mere thought of a rogue cowpie. But small animals are more efficient protein producers and are often allowed within city limits. The average backyard provides plenty of space, typically 800 to 1,000 square meters or about 8,600 to 10,700 square feet. ...

They found that using only backyard resources to raise chickens or rabbits offset protein consumption up to 50%. To reach full protein demand with animals and eggs required buying grain and raising 52 chickens or 107 rabbits. That's more than most city ordinances allow, of course, and raising a critter is not as simple as plopping down a planter box. While pasture-raised rabbits mow the lawn for you, Pearce says the "real winner is soy." Consuming plant protein directly instead of feeding it to animals first is far more efficient. The plant-based protein can provide 80% to 160% of household demand and when prepared as edamame, soy is like a "high-protein popcorn." The team's economic analyses show that savings are possible -- more so when food prices rise -- but savings depend on how people value food quality and personal effort.  

I find it hard to believe an average backyard can produce enough soy to meet a family's protein needs, but that seems to be what they are saying. And as much as I like edamame as a snack, there are only so many ways you can imagine cooking it in meals.