Earlier quoted context omitted.
As of 2016 ~10% of the world's population is undernourished. https://www.worldhunger.org/2015-world-hunger-and-poverty-fa... If you believe that "most of today's populus have barely enough to eat" there is a good chance you have a much more dismal view of the world than actually exists. I'd recommend checking out http://forms.gapminder.org/s3/test-2018
Yes, I do believe that in raw numbers most people have just enough food and water available so that they don't hunger. So the lowest 10% go even below that and face starvation now and then. I doubt that they enjoy the quality of the food they have as much as you enjoy yours. Thanks for the link to worldhunger.org though. It's nice to see that per definition we solved the hunger and poverty problem! I had no idea! Yet…
"The world produces enough food to feed everyone. [...] A principal problem is that many people in the world still do not have sufficient income to purchase (or land to grow) enough food or access to nutritious food."
It's amazing that we produce enough food to feed everyone. The question is how to ensure that everyone has enough access to income to feed themselves. There are two major factors here, the price of food and the income of the person. Both of these can be adjusted to ensure that everyone can eat.
Advances like nitrogen fixing, rust resistant wheat and proper irrigation can push the price of food down. Some of these have the amazing property of being able to be solved essentially once and have the whole world benefit, the green revolution had absolutely amazing ROI, the work of just a handful of people produced wheat that can be raise yields dramatically almost everywhere. It'd be great to see the same thing done with cassava, rice and other staples.
Raising incomes is fairly tricky and even more contentious, but thankfully that is happening as well.