Want to feel confident, sexy and skinner than ever? Go buy a new bra.

After months of wearing my nursing bras—even beyond breastfeeding—then months more of wearing my pre-pregnancy bras that, clearly, didn’t fit right at all, I finally went for a fitting and got some new lingerie. This was last week and I am still on a self-confidence high.

Most women know by now the importance of wearing the right clothes—that is, ones that fit. This contributes more to our self-esteem and body image than the numbers on a scale, whether we know it or not. That’s why we freak out when we find “the perfect pair of jeans.” It’s not the designer label or the degree of stretch in the fabric that makes them “perfect” (though the latter helps). It’s that they don’t make things bulge or pinch or squish or otherwise look and feel morphed. Our bodies are not meant to be constantly sucked in and suspended in Lycra (love you, Spanx, but only on special occasions).

This is especially true for new mothers. To say that our bodies have “changed” is a hilarious understatement. Celebrity obsessed tabloids focus on “baby weight” (and, of course, how quickly the famous can and we should lose it all) but that’s hardly the most dramatic change that occurs when a woman carries, supports and delivers a human being. Our skeleton changes. Our hips aren’t what they used to be because they aren’t where they used to be. So, clearly, new jeans are in order.

But first on the list of new clothes for moms should be lingerie. Perhaps the greatest changes occur in our breasts. They knew we were pregnant before our brain did, instantly getting that hormonal signal to start changing. And change they did.

So why, then, do we save our old bras? I naively figured I’d just wear my old bras after breastfeeding and adjust the straps to make them fit. I understand saving some pre-pregnancy clothes to wear again after things “settle,” but every mom who goes through pregnancy, labor and delivery and, if she chooses, breastfeeding, warrants a brand new lingerie collection.

This may be the most empowering shopping trip of your life. The key is to get a proper fitting. Go to a lingerie boutique or department store, not Victoria’s Secret. There’s nothing wrong with shopping at Vicky’s (I love their sales, too) but the stores are usually staffed by young people perhaps on their first jobs, not trained tailors. I went to Nordstrom, which has excellent customer service and on-staff boob specialists (that’s what I call them anyway). When I learned from my own personal boob specialist that I had gone down a cup size but up a band size, I could finally pinpoint the source of upper back pain that I’d been feeling for months.

I walked out with three new bras and a handful of panties. When I got home, I threw out everything in my lingerie drawer. I didn’t even think twice about how much I spent on the things that no longer fit me. They had to go.

In one shopping trip I improved the way my wardrobe fit, boosted my self esteem and got a sexy, new collection of underthings. It’s moments like these that make me realize that there’s real power in fashion.