Ask any vintage clothing enthusiast: Those nipped in waists aren’t for the faint of heart, and they’re certainly not made for the majority of us, size-wise.If trying to squeeze yourself into a skirt better suited for a 12-year old has ever prompted you to question if everyone in the 1950s and 60s must have been crazy petite, well, you’d be right, at least compared to today’s standards. The fact is, there are a variety of possible reasons—ranging from evolution to diet and cultural shifts—that women really are shaped differently these days.Obviously, that cultural mirror that is fashion has played a role. Brief sartorial history lesson: While the 1920s flapper look and stark uniforms of the World War II era offered a brief reprieve, the “finer” woman’s clothing styles throughout the early part of the 20th century focused on tiny waists and highlighted the “womanly” bottom and cleavage.

The exaggerated feminine silhouette culminated in the 50s, when famed designer Christian Dior introduced “The New Look,” with its emphasis on curvy hip padding and corsets that framed a hyper-svelte center. Cut to the 60s and women’s liberation movement, where you see desexualized styles (think of the supermodel Twiggy, who made waves with her androgynous figure that fit perfectly into narrow shifts and skinny mini’s), followed by the 70s pantsuit, coinciding with the massive arrival of more women in the workplace.

Ultimately, these more “experimental” clothing movements, paired with the ultimate embrace of American sportswear, led to the ‘80s (hello sweatshirts and spandex leggings!) and ‘90s (Think: Kate Moss “heroin chic.”), and the deconstructed, often downright boyish shapes that we think of as ubiquitous today.

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Figure-hugging clothes are by no means extinct, but they now belong to their own category, fondly referred to by fashionistas as “Body Con.” On most days, many Western women don shirts and pants that would be considered oddly baggy and oversized by yesterday’s sharp dresser.

While fashion trends may speak to some of a society’s current values, there’s a difference between these body ideals versus real life, says Kjerstin Gruys, Ph.D. candidate at the UCLA Department of Sociology whose dissertation focuses on the evolution of clothing size standards in the fashion industry over the past century.

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“It would be a mistake to assume that all women in the 1950s had a perfect hourglass physique,” she says. “A society’s ideal bodies are not necessarily the same as our real bodies were at any given time in history.” As she points out, “Why was Marilyn Monroe so famous? It wasn’t because she looked like everyone else, but because she looked so special.”

Gruys has compared women’s clothing in Sears catalogues between 1892 and today, which has offered her a fascinating window into fashion trend versus reality: “In the 50s, Sears advertised tons of highly structured undergarments, like girdles, for sale. It suggests that women were striving for that ideal, Monroe kind of body type, but clearly, it wasn’t so easy to achieve!” Another fun fact Gruys dug up: Marilyn Monroe’s famously 23-inch waist was half an inch smaller than the tiniest size available at Sears in 1955.

Still, there’s no denying that over the decades, as the width and length of our fabric has increased, so have our average body sizes. According to a study commissioned by the Centers for Disease Control in 2002, the average height of women ages 20-74 rose from 5’3” in 1960 to 5’4” in 2002, where it remains today. The average weight for women in the same age group rose from 140 pounds to 164 pounds. A healthy weight for a 5’4” woman is between 110 and 140 pounds.

The study also found that women aged 20-29 were nearly 29 pounds heavier on average in 2002 compared to 1960. Perhaps the most alarming statistic: The U.S. Department of Health and Human Services estimates that a whopping 64.1 percent of American women over the age of 20 are considered obese. Between 1950 and 2000, American obesity rose by 214 percent.

While we may be taller and curvier than ever—more fat equals larger breasts and bottoms—we’re far from hourglass: Some research links our expanding waistlines and extra belly fat to an increase in cortisol caused by modern-day stress. Our figures are more, gulp, barrel-like. The large-bottom line? No wonder those waist-cinching vintage clothes don’t fit.

How did this happen? Fashion aside, the widespread availability of illness-fighting antibiotics and other medical advances during the 50s helped contribute to healthier women, and the disease-free are more likely to thrive in terms of growth. (Other theories as to why we’re taller range from access to better nutrition to new ethnic demographics in the U.S.)

But when it comes to the more dramatic weight-related stats, something else happened during the era that may help explain today’s relatively larger BMI’s: the mainstreaming of television and advent of fast food. It marked the beginning of a country growing more accustomed to sedentary lifestyles and TV dinners, the latter of which was a completely foreign concept to housewives who normally slaved away in the kitchen whipping up homemade meals. Processed foods weren’t just hyper convenient, they seemed downright glamorous.

“In the 50s we’re looking at a huge surge and trendiness in processed food,” says Gruys. “During the Red Scare when Americans were terrified of Communism, our government put a lot of effort into comparing the Soviet lifestyle to ours by emphasizing the luxury of our accessibility to pre-made meals and fancy kitchen appliances, as opposed to having to make things from scratch like the ‘poor Soviet women’ had to.”

Anyone who’s ever compared the sodium, preservative, calorie and fat counts of most frozen meals can attest to the undeniable fact that fast food contributes to the kind of expanding waistlines that simply can’t squeeze into hourglass-shaped dresses. Speaking of fast food, the venerable McDonald’s opened in 1955 (you’ve heard of it?), and to the “billions and billions served,” we all know the rest is super-sized saturated fat history.

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As much as we now know how damning these so-called “innovations” have become to our health, the prognosis isn’t all bad. There are certain benefits to being large and in charge. For instance, some scientific research claims that tall people live longer.  And a 2009 study found that the underweight and extremely obese not only die earlier than people of normal weight, but get this: Their research suggested that the overweight may actually live longer than people of normal weight. Yet another report in the Proceedings of the National Academy of Sciences theorizes that we will evolve to become still heavier, yet shorter, due to a hypothesis that hinges on the idea that “there is natural selection against women being slender,” and that “plumper, shorter women tend to bear more children.”

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Now back to looks. There’s no doubt that culturally, recent movements suggest that as our aesthetics have shifted from curvy hourglass figures and then skeletal runway models over time, we may be tending toward a more realistic ideal in terms of what is considered beautiful. The 2004 Dove Campaign for Real Beauty springs to mind, where average-sized women were depicted wearing nothing more than their skivvies (and one would assume, some powerful deodorant and body lotion?). The public responded with unparalleled enthusiasm, and since then, even the glossiest of fashion magazines have embraced the practice of depicting “plus-sized” models (read: average American woman-sized), every now and then at least.

Ironically (not), arguably one of the most, er, inflated visual portrayals of the female body, Playboy—another 50s-era invention—has adopted the opposite concept: According to a study published in British Medical Journal, the magazine’s models have slowly evolved from Marilyn Monroes to more like Maria Sharapovas, in that the look has become more androgynous, perhaps coinciding with our society’s steadily growing obsession with fitness. By analyzing the centerfolds’ body measurements between the span of 1953 to 2001—grueling work, we’re sure—researchers found that bust and hip measurements have decreased and waistlines are comparatively less whittled for a straighter body, just like say, a tennis player’s body might look.Proof that even svelte tennis players won’t fit into vintage clothing!

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