The prescribed human diet
This verse clearly identifies the food that God designed for humans. It is clear that humans were intended by their Creator to eat fruits, vegetables, nuts, seeds and roots, and not animals.
One might argue that the previous verse also gave humanity permission to eat any kind of fish or animal: "Rule over the fish of the sea and the birds of the air and over every living creature that moves on the ground." (Genesis 1:28) However, this does not say that the fish, birds and animals will be our food as this verse clearly says. It says that humans may "rule over" them. The correct interpretation of this statement is not that we would kill these creatures, but that we would care for them.
To "rule over" does not mean that we maliciously rule over them, and take advantage of them. A king or a government, for example, may rule over the people. But their purpose is not to hurt the people but to care for and help protect the people.
This is the same with regard to fish, birds and animals. God asked that we care for the animals. That we help protect them. Not kill them for our food.
We find later in Genesis that God did permit the offering and eating of animals later on. But this was not necessarily His preference. Because there was little fruit, grain and vegetable foods available in the dry Middle East, they needed to kill animals for food. He thus permitted them to eat limited kinds of animals. But these were to be eaten only after they completely drained the animal's blood and offered it to Him.
God's preference, however, is that we eat fruit, vegetable, grain and baked foods, after first offering them to Him. For example, we find God's statement from Isaiah:
"The multitude of your sacrifices— what are they to me?" says the LORD. "I have more than enough of burnt offerings, of rams and the fat of fattened animals; I have no pleasure in the blood of bulls and lambs and goats." (Isaiah 1:11)
Sufficiency without bloodshed
Plant-based foods not only provide all the vitamins, minerals, proteins and fats that our bodies need: They also prevent disease. Research has found that plant-based foods contain hundreds and even thousands of phytonutrients that prevent cancer and many other diseases. The reason plant-based foods do this is quite simple: God intended humans to eat plant-based foods, as indicated by this verse in Genesis.
Since these foods can be eaten without shedding the blood of innocent animals, the vegetarian diet was the preferred diet for many of the Prophets. This includes Daniel, Isaiah, John the Baptist, Isaiah, as well as Jesus and his followers - with the exception of fish.
It is clear from Biblical statements that following the exodus, when Moses and his followers were traveling through the desert with little to eat, that animals were okay to consume if the blood was thoroughly drained. But it is clear that before and after the exodus, the prescribed food for humans remained plant-based.
Yet as always, God still gave us the choice to follow His wishes or not.