With more than 15 million data points about women’s breasts, Heidi Zak and her company, ThirdLove, have arguably more information about boobs than anyone out there. Turns out that nearly 80% of us are wearing the wrong size bras! (This has spurred the “half size” revolution.) Listen in as Heidi schools Brit and her Brit + Co co-founder, Anj on breast shapes, bra mistakes we’re all making, and so much more. Young or old, AA to DD (or bigger!), this is an episode you’ll want to share with all of your girlfriends.

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