Wanting vs Conditioning

Why does even the bad food/ stuff after awhile taste better if I keep eating it? Or if I put it on my husbands plate? Is there something in my brain chemically making that happened? If I spent years of making myself eat protein bars, shakes, etc. because I paid for it, and that’s all I have (scarcity mentality) then I guess I’ve conditioned my brain to (like I do with bad stuff in life) subconsciously immediately tell myself it tastes good and want more. No matter the low fat, grainy texture, cardboard taste, etc.