7: An Experimental Mutiny Against Excess - Jen Hatmaker
The author is happily Christian and there is much talk of Jesus, so if that's not your thing, you might have a problem with this book.
I'm not happily Christian, but I still enjoyed reading this very much. The author tries an experiment for seven months: Each month, she picks a theme of excess in her life to pare down. Food, clothing, waste, etc. It was very interesting. It was also refreshing that she included her failures as well as successes in the book. Change is not easy, and she doesn't gloss over any of it.
I also really dig that she's not too much a hypocrite (not more than any of the rest of us anyway!). Her family started a mission for the poor that gives directly to the needy, without funding a nonprofit. They cook for the homeless. They give stuff directly instead of donating to an organization, or fancying up a place of worship. She takes "What would Jesus do?" much more seriously than many, but still comes off as light-hearted and willing to make changes and continue working on excess once the experiment is over.