Debbie had numerous health problems when she was growing up. French Bulldogs have genetic spine and hip problems which cause temporary paralysis and extreme pain. Debbie also suffered from hair loss, inconsistent bowels, allergies, and erratic behavior. Her vet suggested a $10k surgery to fix her spine and expensive medications for everything else.
When she switched her diet completely to human grade foods, her life changed almost immediately. She has not had a health problem since. She has not had an episode of temporary paralysis or extreme pain. Her fur is thick and shiny. Nail, eyes, and skin are healthy. Debbie has a small poop once a day and her behavior has calmed down.
The way we like to think about this is no different than human nutrition. If you were to feed a kid chips and crackers every day, their bodies would fight against them. When dogs eat low grade kibble every day, their bodies fight in all the same ways.