While reflecting on a male friend's persistent questions about whether another acquaintance's breasts were "real" or "artificial," Brunettes Blog blogger Ginny comes up with a much more plausible... and mundane... explanation for beauty standards (which are remarkably plastic over time and culture) than simple "evolutionary fitness signaling:" scarcity. (Emphasis mine.)
Another possibility ... is that exacting standards of beauty are not primarily about evolutionarily-coded fitness signals, as we’re so often told these days. Instead, they’re about status and acquisition. Women with lovely faces and perfect bodies are rare, especially as today’s “perfect body” is tiny with large breasts, not a common naturally occuring combination. Anything rare can be assigned a high value, and gaining possession of a rare valuable grants status to the possessor… especially when competition comes into play, as it seems to do with partner-choice. If a naturally-perfect body is a diamond to shine on the arm of a victorious male, then a surgically-enhanced perfect body is cubic zirconia: just as lovely, but easier to come by and therefore less valuable.
Source: The Brunettes Blog
You know what? Even if the stwatistical correlations of hip/waist ratios and ovulation detection were true it still wouldn't explain the much, much larger (but usually very much more critical to local cultures and times) distinctions of skinniness in women when food is abundant, corpulence when food is scarce, flabbiness in women when physical labor is obligatory, buffness when most work is done at desks, pale skin when most women laborers do field work, tans when most labor is factory or office work, and, especially, blonde women when blondes are scare or "exotic Asian women" in those parts of the world where... there are nearly two billion other Asian people. Oh, and women with clear, flawless skin when insects, acne, and sunburn was prevalent, and women with lots of tattoos, brandings, and piercings once sunblock, benzoyl peroxide, and sunblock become de rigueur.
Feel free to point out that evolution might have biased humans to equate that which is scarce with that which is beautiful. We're certainly evolved creatures (as opposed to what? Spontaneous generation?) But a preference for that which is rare is a very different matter than straight up sexual selection.