He died spiritually. ICR agrees that Adam's sin inaugurated spiritual death. Yet Dr. Ross teaches that Adam's sin had nothing at all to do with physical death. He also relates human and animal meat eating to the natural order of God's creation. It is difficult for us to see physical death as something good since a spiritual being's death implies so much more than it does for plants and animals.
All organisms are like engines in that they only can operate through the consumption of energy.
Plants convert solar energies into sugars, starches and fats that they later draw upon for life functions. But it is physically impossible for any photosynthetic system to sustain the large energy expenditures common for advanced animals. For these animals to engage in their activities, they must consume the stored solar energy available in plant tissue. This requires the physical death of that plant tissue. For greater energy efficiency, animals will need to consume the tissue of other animals.