In New York Timescolumnist Nicholas Kristof’s column on Sunday, he recounts the story of then-14-year-old Hannah Salwen and her dad Kevin, and how a chance encounter with a homeless man catapulted their family into swapping their high-end home for a more modest abode and donating half of the proceeds to charity. Just reading that story either gives you the warm fuzzies (“So generous, so inspiring!”) or the heebie-jeebies (“Not everyone has that luxury, the show-offs”).

To push you a little more toward the warm fuzzies, I’ll point out that not only did the Salwen family’s “sacrifice” fight hunger in Ghana through their donation to the Hunger Project, but it gave them the added benefit of becoming a closer family—both literally and figuratively. By moving to a smaller house, this family of four was forced to be around each other more often, which they discovered they actually enjoyed.

“We essentially traded stuff for togetherness and connectedness,” Kevin Salwen told the NYT. “I can’t figure out why everybody wouldn’t want that deal.”

At the heart of this story lies a deeper critique of the American obsession with consumption and the “bigger is better” mantra. We Americans shun the word “sacrifice,” but studies find that trading stuff for time with people quite often makes us happier, healthier, and more sustainable. Kristof cites one of my favorite scientific findings: When we act altruistically (volunteer, donate to charity, etc.), we get the same neurological high in our brains that food and sex impart. Being good really does feel good.

Welcome to conscious consumption: it’s not just about what we buy (even if it is fair-trade, organic, local), it’s also about being intentional with what we already own and cutting out the excess. On a related note, because of the recent recession, Americans are buying less, but doing more. The Department of Labor, keeping tabs on how people spend their time, found that Americans were cooking or participating in “organizational, civic and religious activities” more in 2008 than in 2005. Cooking more? That’s music to Michael Pollan’s ears. Engaging with communities more? That’s a hopeful and meaningful sign of progress toward sustainable, climate-friendly cities.

The Salwens are preparing to publish a book, The Power of Half, about their experience of giving up bigger for better and how others can similarly donate excess in their own lives for a good cause. Can a teenager’s enthusiasm for social equity encourage a bigger shift toward conscious consumption?

For more on the Salwen family’s adventures in altruism, watch this video from the Today show: