It is naive to believe that these 86%, assuming the numbers are true, have any impact on the food production at all.
Of all the cropland we have, 57% is used to produce human food and 43% is used to produce animal food.
https://ourworldindata.org/land-use-diets#more-plant-based-d...
The whole point is that you need way more crops in general to "produce" the same amount of calories & proteins. That's because feeding the animals with crops instead of eating them is highly inefficient in comparison to eating them directly. "As an example: beef has an energy efficiency of about 2%. This means that for every 100 kilocalories you feed a cow, you only get 2 kilocalories of beef back."
https://ourworldindata.org/land-use-diets#livestock-waste-a-...
With how much meat is eaten right now, there is just no way we have enough grazing land to produce enough meat. 99% of meat comes from factory farms. [1] These animals are always fed with crops, so there will always be land usage to product food for animals. And it is way more inefficient.
[1] https://www.livekindly.com/99-animal-products-factory-farms/