What proven technique is circulated for stretching ground meat when incorporating animal protein sparingly?

Replacing half the meat with cooked, finely mashed beans or oats

When incorporating animal protein, which is typically the most expensive component of any meal, into a budget plan, the focus must shift to extending its volume without sacrificing too much texture or flavor. A proven technique shared in frugal cooking circles involves extending ground meat by substituting a substantial portion—often half—with cooked, finely mashed substitutes. The most commonly recommended additions for this purpose are cooked lentils or black beans, or sometimes oats. This substitution maintains bulk and texture in dishes like chili or taco fillings while significantly reducing the overall cost of that specific meal element.