Anthony initially wanted to trick the Elves, as he knew they had some war reserves including Elf Beans that could feed hundreds of thousands of people for a month.
Of course, the Elves would not give up their Elf Beans, but Anthony intended to use the beans as a starting point to secure some other foodstuffs from the Elves. If they refused to sell him the Elf Beans, they could perhaps sell him some plant tubers or dried fruit, right?
Especially one type of tree called Pink Palm. Once it's cut open, the heartwood inside can be eaten directly, and when dried and pounded into powder, it can be used as flour.
As for the wild vegetables and sprouts that sprung up all over the mountains after rain, the Elves could not possibly exhaust the supply. If people were mobilized for foraging, they could sustain many. The Elves' utilization rate of the forest resources was astoundingly low.