George Washington Carver did not invent peanut oil but developed numerous techniques for cultivating peanuts and promoted their use in various products, including peanut oil. His work in the early 1900s, particularly around 1916, led to the popularization of peanut oil as a cooking oil and its incorporation in various food products. Carver's research and advocacy significantly contributed to the agricultural and economic importance of peanuts in the United States.