“Change: From the Inside Out or the Outside In?” the headline read, reflecting a popular trend today—the idea that outward changes like a makeover or better posture can be an easy way to change how we feel on the inside—and even change our lives.

It’s an appealing concept—who wouldn’t want improving our lives to be as easy as a new look? Many of us have learned the hard way that changing deep-rooted habits can seem nearly impossible. Focusing on simple external changes offers hope that there is a quicker path toward improving our lives.

But although such changes can improve our lives,…