So if you saw my videos back in the day, I ate around 10 pounds of potatoes per day for 10 days. It was easy and tasty. I am not necessarily recommending you do it, because I think that fruit is easier and healthier, but I did it and many people in the world have done fine on potatoes.
I think that if you are eating cooked food, potatoes are a good way to go and I think they taste great. Though they are somewhat dry, like all cooked foods.
Near the end of this video I show the nutritional info of potatoes + lettuce + almonds.
So check this out:
There are 40 million acres of lawns in the United States.
On average, an acre of potatoes produces 106 pounds of potatoes per day.
106 pounds of potatoes = 38,228 calories. This means that one acre is enough to feed around 10 active people.
So, if 40 million acres were planted with potatoes, 400 million could be fed.
The numbers for the potatoes are based on calculations performed after harvest. This means that it accounts for crop losses.
Now a person can come up with something like the fact that potatoes might not grow very well in all the places where grass grows. To which I can respond, that grains are grasses and grains could be grown instead.
So consider that. We already have enough "farmland" as lawns to feed the whole country.