This isn't true at all. The federal government's School Breakfast Program started 3 years before the Black Panther's program. During it's first year, it was already serving many times the number of children than the Panther's program served at its peak (despite being a pilot program at the time)[1]. It was part of the much larger Child Nutrition Act, which itself built on the even earlier National School Lunch Program and Special Milk Program.

[1] https://www.fns.usda.gov/sbp/program-history [2] https://en.wikipedia.org/wiki/School_Breakfast_Program