Ahh, Kate Hudson. She’s an Oscar-nominated actress. She’s a bestselling author. She’s a successful entrepreneur. She’s a beauty trendsetter. She’s an undeniable Hollywood A-lister despite not having done a helluva lot onscreen over the past decade. One of the reasons for this omnipresence is, of course, nepotism. (Who doesn’t love Goldie Hawn.) But a lot has to do with that relentless joie de vivre. When you see Kate Hudson on the cover of a magazine flaunting her “fun, flirty, and fit” figure,...