Q: Why does the USDA specify 'American Indian/Alaska Native' foods as a separate food group?
On November 6, 2000, President Clinton signed Executive Order 13175, Consultation and Coordination With Indian Tribal Governments, "to establish regular and meaningful consultation and collaboration with tribal officials in the development of Federal policies that have tribal implications".
Food sovereignty began in 1996 as an international movement. That movement and the executive order meant that the USDA had to consider its policies "with tribal implications". Beginning in April 2004, the USDA began adding, to its Standard Reference, the nutrient content of "American Indian/Alaskan Native Foods" as a distinct category. Ultimately, 165 foods were added.
Additionally, the USDA improved its support for producers of such foods.
USDA Resource Guide For American Indians & Alaska Natives, December 2016
4.1 Agriculture, Food Sovereignty and Traditional Foods
As stewards of the land, Native producers are in a unique position to speak on local agricultural traditions and priorities. In this section, we provide you with an array of programs that support agricultural producers, the ability of each tribal nation and its citizens to feed its people, and the recognition that Native traditional foods are important to the health and well-being of Native people.
Q: For example, what is the difference between 35137 - Cornmeal, yellow (Navajo) and 20020 - Cornmeal, whole-grain, yellow?
Nutrient content — as far as the USDA is concerned — nothing more, nothing less.