90% of USA's farmland is grown to provide food for our meats (cows, pigs, chickens, etc). So if instead of growing all this corn for our animals, it could be used to provide it to people. This is because 90% of the energy the cow consumes from corn is lost through normal metabolic processes. Again when we eat cow, we loose 90% of the energy in the meat through metabolic processes.

Therefor if everyone was a vegetarian then we could use the 90% of land to provide for people.

I however will never stop eating meat, and the USA will never stop raising cattle. Its not a matter or having enough food for people, its a matter of distributing it to the people.

Next all types of food we consume are GM (selective breeding). There is a big difference between genetically modified foods and genetically engineered foods. Your talking about GE foods, where you take genetic information from one organism and splice it into the genetic information of another organism.

If you selectively breed your plants they are now considered GM foods. (Example: If you grow corn and half of your crops are small, while the other half are huge, your going to take the seeds from the large plants and grow them next years harvest.... this is GM). I had a class in undergrad that went over this, but the media mis interperates this material. Even Wiki is wrong on the difference between GE and GM foods.

Over the last 200 years people have been doing that, so every plant/seed we have has been selected in the past years.

I cannot confirm that GM = selective breeding, but that was what i was taught in undergrad so either im definitely wrong, or the technical terms have changed in the last 4 years.

But all in all, yes i think there would be enough food to feed everyone because we would use less farmland in providing food for our cows.

Organic and vegan are two different issues.

There is probably not currently enough organic food to feed everyone.

A vegan lifestyle, however, is "lower on the food chain"--fewer resources are used to produce grains and vegetables than are used to produce meat, so if the whole world was vegan there would be less stress on the world's resources.

I'd go one step farther. I don't think it is possible with today's knowledge to support an organic food supply for the entire world. Without the benefits of pesticides and certain fertilizers there simply isn't enough acreage.

As for the vegan yea we could do that in a snap. It would actually decrease the burden on the planet.

The world would become over-populated with cows, and they'd eat us!!

Yes, because here is plenty of food in the world now. The problem at this moment is not lack of food, it is the distribution of food. However, a change to organic food would result in much lower production per acre and eventually this would be disastrous. In my view, the vegan lifestyle is a North American/European phenomenon, and it will not be popular in the rest of the world.
My prediction is that the world will warm and we will see an incredible increase in the production of meat and grain in Russia and Canada, and a decrease in other areas of the world, but not enough to offset the increase in the northern latitudes.
Also, those governments who are authoritarian will actively promote GMO's with the result that, due to cross pollination, eventually most grains will contain some genetic material from GMO's.

Currently there is plenty of food for everyone, just like others are saying there is a lack of distribution. Even repairing this distribution, there are organizations out there that will stop at nothing to steal the food from the poor, and then use/stockpile it for themselves and hold the poor at ransom.

Also research shows that almost half of all food in the world is wasted, just thrown away. A lot of it is due to our selectiveness of food, and supermarkets/restaurants ensuring they have the quantity to supply the masses. If a trend changes, though that food is discarded once it is expired.

Even further than that, the poverty situation across the world helps perpetuate this problem. Although the increase in vegetable/organic foods would eventually raise the price of those foods, and those who are homeless and very poor, would still be in the situation they are now.

With gene manipulation, I believe selective breeding and some small modification are a great idea, but I also believe that the food created should be researched thoroughly, to ensure there are no side effects from the food created. A while ago, I heard about scientists changing bacon/pig and making it a lot more healthy than it is now. If we could create healthier foods, but keep the foods available, perhaps our obesity problem would be solved. Then again, it could get worse, as it could spawn people to eat 2x as much.