Why are the French fries brothers called Dr. Tang?

The origin of the name "Dr. Tang's three French fries brothers" is not clear. It may mean that Dr. Tang Jiayu is a good friend, and all three have doctors' jobs, or it may mean that Dr. Tang Jiayu often shares French fries with two friends. Due to the lack of conclusive evidence and official explanation, we can't determine the exact meaning of this name.