Soybean meal (SBM) is the major source of amino acids (AA) and energy in diets for swine throughout the world because SBM has an AA profile that matches the requirements of pigs and AA in SBM have high digestibility. In the U.S., nearly 20% of all SBM produced is used to feed pigs. However, AA in diets can also be provided by feed-grade synthetic AA and diets based on corn and synthetic AA have been thought to also increase diet net energy and reduce N excretion and carbon footprint. With the addition of synthetic AA in diets, it is possible to reduce the inclusion of SBM and formulate diets with reduced crude protein. However, recent data indicate that pigs of modern genotypes utilize more dietary protein than older genotypes and the net energy may, therefore, not be increased in diets that contain less SBM and more corn and synthetic AA. Therefore, the objective of this experiment was to test the hypothesis that diets based on corn and SBM and limited quantities of synthetic AA contain net energy that is not different from diets based on corn and larger quantities of synthetic AA.