We've all seen the magazine covers. We've been informed what the peak measure of female perfection is. Is it a tight butt? Sure, that'd be nice. What about slimmer thighs? Yeah, that's important too. But the slimmest aspiration women are supposed to chase these days? Why, flat abs, of course.
But here's the "burn-your-belly-fat" industry's dirty secret: From an evolutionary standpoint, women simply aren't cut out for flat abs. In other words, if flat abs are the new standard of health and beauty for women, then they are being set up to fail.
Of course, the pressure on women to be skinny is nothing new. This is America, after all, where the average runway model meets the medical criteria for anorexia. That more or less tells you all you need to know about the absurdly high value Western culture places on skinniness, particularly for women. Nowadays, we tend to take this as a given, but of course, it wasn't always like this. In the 1800s, Americans were often heavier than their European counterparts, thanks to an abundance of empty farming land, and being full-bodied was considered an indicator of higher social status.
It's unclear exactly when this changed. Some scholars point to the women's rights movement of the mid-20th century. Under that theory, women wanted to do away with traditional depictions of beauty and femininity, which emphasized wider hips and curves as an indicator of childbearing ability. Others, such as historic gastronomist Sarah Lohman, peg the mid-1800s as the turning point, as that's when diets emphasizing skinniness began to gain wider currency in America.
In the form of abdominals taut enough to serve a meal on, the fitness industry has finally found a goal that a very large number of women could be convinced to fight against their very biology to achieve.
As it turns out, women are biologically predisposed to store fat in their abdomens more efficiently than men, since belly fat serves as protection for the reproductive organs and fetus during pregnancy. As a result, women's bodies naturally begin storing fat cells in the belly area during adolescence and young adulthood in preparation for childbearing. Men, of course, don't have such a biological predisposition, and thus have an easier time maintaining washboard abs.
One could argue that the cultural preference for skinniness in women is, in a sense, imposing men's biological expectations onto women. Women's bodies, unlike men's, are expressly designed to hold onto fat. As Science Daily explains,
It's a paradox that has flummoxed women for generations – their apparent ability to store fat more efficiently than men, despite eating proportionally fewer calories ... On average, women have 6 to 11 percent more body fat than men. Studies show oestrogen reduces a woman's ability to burn energy after eating, resulting in more fat being stored around the body. The likely reason is to prime women for childbearing.
So while Michelle Obama's arms and toned glutes are hard to achieve, biology dictates that flat abs are that much further out of reach. And the fitness and beauty industry seem to have discovered that this makes them that much more tantalizing. In the form of abdominals taut enough to serve a meal on, the fitness industry has finally found a goal that a very large number of women could be convinced to fight against their very biology to achieve.
How did they convince perfectly reasonable women of this? First, through the illusion that flat abs are attainable. That's as easy as a Photoshopped celebrity cover shoot. But the selling of flat abs as healthy (yes, even though they don't naturally occur in healthy women) has been just as effective. Where do flat abs cover lines appear most frequently? On fitness and health magazines, of course.
This is of course part of the selling of thinness as healthier than fatness, to the benefit of the $20 billion diet industry. But what you are unlikely to see in Shape or Women's Health is an article on the fact that, as it turns out, having flat abs isn't always healthy, and being "overweight" isn’t always unhealthy. In fact, having a Body Mass Index (BMI) that’s considered “overweight” can, in certain situations, be better for your health than a “normal” BMI.
Part of the confusion comes from the mistaken belief that weight (or BMI) goes hand-in-hand with health. More weight means you're less healthy, and vice-versa, right? Wrong. While the two are correlated to some degree, there’s a crucial element of health that neither weight nor BMI capture: Body fat percentage, or the percentage of one’s weight that’s comprised of fat as opposed to muscle.
Many people are metabolically obese normal weight (MONW), colloquially known as "skinny fat." This means that, while their BMI and weight may be within normal range, they suffer all the same health risks as obese people — type 2 diabetes, heart disease, high blood pressure, abnormal cholesterol, and so on — because their body fat percentages are too high. These are often people who eat fast food, never work out, and look thin anyway.
There are plenty of women's articles on being skinny fat, putting the reader on notice that even being thin is not enough, but there aren't many on the fact that being “overweight” doesn’t necessarily mean you’re going to fare worse than your skinny companions.
Scientists have identified something known as the “obesity paradox.” While overweight people are generally at a higher risk for heart disease (as well as arthritis, kidney disease, diabetes, cancer and HIV), they also have a better chance of surviving those ailments than their thinner counterparts do. Even more strikingly, a 2013 study of almost three million people found that people with a BMI between 25 and 30 — which is considered overweight (but not obese) — have the highest survival rate of anyone.
According to cardiologist Carl Lavie and others, the take-home message is simple: When it comes to long-term health, what matters is working out, not weight or BMI. “The worst prognosis is in the thin person who’s not physically active,” Lavie says. “They do worse than almost anyone else. If you’re fit, it doesn’t matter nearly as much what you weigh.” Long story short: Being skinny can be very unhealthy, and being a bit overweight can be healthy.
But here's the most grievous admission from this phenomenon: Women in particular have an additional reason for reconsidering the value of flat abs — especially mothers. As evolutionary biologist Steven J.C. Gaulin explains, women have evolved to maintain a relatively low weight prior to their first child. That’s because smaller babies have an easier time passing through the birth canal, and a skinnier mom generally results in a smaller baby. But a heavier baby is usually healthier — and giving birth reshapes the pelvis, making it easier to give birth to heavier children in the future.
Women who gain weight after giving birth, then, aren’t succumbing to stress or postpartum depression or any of the other explanations bandied about. They’re just following the evolutionary imperative of their bodies and preparing themselves to give birth to an even healthier child the next time around.
None of this research implies that being morbidly obese is healthy, or that the things people do to get washboard abs — working out and eating healthfully — are bad. But if the goal is to be healthy, it’s much wiser to focus on fitness and physical activity, and not on weight, BMI, or flat abs.