In his later years Tesla became a vegetarian. He wrote: "It is certainly preferable to raise vegetables, and I think, therefore, that vegetarianism is a commendable departure from the established barbarous habit." Tesla argued that it is wrong to eat uneconomic meat when large numbers of people are starving; he also believed that plant food was "superior to it [meat] in regard to both mechanical and mental performance". He also argued that animal slaughter was "wanton and cruel".
Nikola Tesla, "The Problem of Increasing Human Energy". Century Illustrated Magazine, June 1900.