(nataliej/Flickr)

I am not fat. At just over 5 feet tall and 101 pounds, I'm actually closer to thin. It shocks me to even write this, but after a zaftig childhood and a curvy-bordering-on-chunky early adulthood, I find myself, in middle age, after two kids, to have reached my "ideal" weight.

But lately I wonder if it's really worth it.

From the outside, thin is surely better. Other moms tell me I look great. I can consider bikinis. I appear far younger than my actual age and, with a perky, teen-sounding BMI of 19.9, I fit in my daughter's Forever 21 tops.

But peek inside my brain: it's alarming.

(Rachel Zimmerman/WBUR)

I spend an inordinate, and frankly embarrassing amount of time thinking about food, planning meals and strategizing about how to control my weight. It's on my mind pretty much every waking hour of every day and the details are painfully banal: how many pumpkin seeds in my nonfat yogurt; will a green smoothie pack on an extra ounce or two; can I eat dinner early so my weight the next morning will be optimally low?

If I don't exercise (Every. Single. Day.) I get depressed. If I stray from my short list of accepted foods, I can spiral out of control. My life is bound by a strict system of controls and rigid rules (maintained with a pack-a-day gum-chewing habit) that keep my weight in line. These include daily digital scale checks that set my mood each morning: 102.9 is bad news; 100.4 gets me high. Trivial? Yes. A shamefully first-world problem? Absolutely. But, sadly, true.

And widespread. A new report on women and body image conducted by eating disorder experts at the University of North Carolina makes clear the scope of the problem: a mere 12 percent of middle-aged women are "satisfied" with their body size. (An earlier study put the number at 11 percent.) What's worse, perhaps, is that even those relatively content ladies are troubled by specific body parts: 56 percent, for instance, don't like their stomachs. Many dislike their skin (79 percent unsatisfied) or faces (54 percent unsatisfied) or any other parts that suggest, in Nora-Ephron-neck-hating-fashion, they are aging.

The author as a not-quite-svelte child, in an undated photo from the 1970s.

The very first sentence of the study, published in the highly un-sexily titled Journal of Women and Aging, makes clear that women who are happy in their own skin are a rare, exotic breed; specimen worthy of study by a crack team of anthropologists. The report begins:

We know strikingly little about the intriguing minority of women who are satisﬁed with their body size. Deﬁned as having a current body size equal to their ideal size, body satisfaction is endorsed by only about 11% of adult American women aged 45–74 years.

If you dig a little deeper into the study you'll find that this "body satisfaction" is fragile. Women were asked if they'd remain satisfied if they gained five pounds. The answer (duh): "No."

And these so-called "satisfied" women seem to spend a huge amount of energy maintaining.

They remain vigilant and work hard to keep themselves at what they consider to be an acceptable shape, says study author Cristin D. Runfola, Ph.D., a clinical assistant professor and Global Foundation for Eating Disorders scholar at the UNC Center of Excellence for Eating Disorders.

The study, which looked at a sample of 1,789 women across the U.S. age 50 and older, found:

Intriguingly, satisﬁed women appeared to exert considerable effort in achieving and maintaining their satisfaction — a sizable number of satisﬁed women engaged in weight monitoring, weight-management behaviors, and reported that their self-evaluation was moderately or strongly inﬂuenced by weight and shape status. Thus, in contrast to effortless satisfaction, achieving body size satisfaction appeared to be an effortful endeavor that included some of the same behaviors seen in body dissatisﬁed women.

"It's disheartening to see that for these women, it was so important to be a specific size and shape," Runfola said. "Are they satisfied just because they're fitting this mold that looks good to society? Ideally, we would like people to base their satisfaction on who they are, what they do and not so much what they look like."

She's right, but it's a rare middle-aged woman who delights in her own body. (An aside: Runfola said this research began because so many middle-aged women were showing up at the clinic with eating disorders; the stereotype is that such problems afflict only younger women and girls, but Runfola said about 50 percent of her clinic patients are women 30 and older. Of course, some men have body issues too, but let's face it, these are mainly female troubles.)

For so many of us, just when we should be out there enjoying the lives we've created over decades, we're obsessing over our hips and skin and post-childbirth bellies. Personally, I think about how twisted my own priorities can get sometimes: instead of enjoying my great good luck — two smart daughters who sing and climb and do math puzzles, a job I love, a spouse who has never in 11 years of marriage said anything negative about my body — I'm hunkered down counting out my allotment of pepitas for the day.

But maybe this is just the cost of staying thin. We know from research that people who tend to lose a lot of weight and keep it off generally remain vigilant to the point of obsessive; they're always on guard. In her sweeping 2011 New York Times Magazine story, "The Fat Trap," Tara Parker-Pope quotes Kelly Brownell, a food policy and obesity expert at Yale, about a small cadre of successful weight-losers tracked in the National Weight Control Registry:

“You find these people are incredibly vigilant about maintaining their weight," Brownell told Parker-Pope. "Years later they are paying attention to every calorie, spending an hour a day on exercise. They never don’t think about their weight.” Janice Bridge, a registry member who has successfully maintained a 135-pound weight loss for about five years, is a perfect example. “It’s one of the hardest things there is,” she says. “It’s something that has to be focused on every minute. I’m not always thinking about food, but I am always aware of food.”

Can such intense vigilance endure without taking an enormous psychic toll? Must we continue our un-ending competition over who has the best mom abs?

Some think not. The latest trend in addressing many of these entrenched questions of weight and body image hinges on relinquishing such white-knuckle “will power” in favor of self-compassion.

Jean Fain, a Boston-area psychotherapist affiliated with Harvard Medical School and author of the book "The Self-Compassion Diet: A Step-by-Step Program to Lose Weight with Loving-Kindness," makes the excellent point that "this is America and the perfectionistic standards are unreachable." She says that no one is ever fully happy with everything — feelings naturally wax and wane and "to think body satisfaction is an achievable and sustainable state is unrealistic." Body realities are different at age 20 and 30, 50 and 80. The key, she says, is to not let all of these little body imperfections rule our lives, but rather to notice them, allow yourself to feel them even if they're painful and then get back out there and live a "meaningful, deliberate life."Of course, that's easier said than done; these food prison shackles have been in place a long time.

In the 1970s, my mom and I did the grapefruit diet together; she took me to a fat-farm in upstate New York where we fasted for a week; mornings, in the dark, I jogged with her at a track in Red Hook, Brooklyn, when practically no one else jogged (I'm pretty sure we wore Keds). My early desire to be a dancer didn't help matters; nor did my summer choreography course at Harvard where I learned how effective vomiting and laxatives can be for weight control. Even now, when my mother comes to visit, she tiptoes into my bathroom each morning and asks: "Is your scale right?" She's in her 70s; it never ends.

For me now, approaching 50, I'm trying to imagine a softer-edged life; less brittle rigidity and more juiciness. Recently, I've been troubled by my self-imposed food prison — an existence that I'd never, ever wish upon my daughters. I've sought help to change. But weaning myself off my daily scale addiction hasn't been easy, nor has introducing new types of foods into my day: yogurt with fat and plump avocados, a fresh, warm blueberry scone now and then, and maybe a few walnuts.

Emily Sandoz, a Ph.D. clinical psychologist and assistant professor of psychology at the University of Louisiana at Lafayette, studies what she calls "body image inflexibility" and has endured her own struggles with weight and bad body image. Her forthcoming book: "Living with Your Body and Other Things You Hate," details a fairly new approach that's gaining traction called Acceptance and Commitment Therapy (ACT). The theory behind ACT is that only by actually working through our anxiety and deep anguish and body hatred will we be able to focus on the much more important business of living meaningful, vital and psychologically flexible lives.

In ACT, patients are encouraged to face all those waves of body-hating awfulness — "I am fat," "I'm disgusting," "I don't deserve to eat" — head on. The research suggests that fully wading into this cesspool of distress allows the feelings, over time, to dissipate and lose emotional power. Studies have found that "ACT is [not only] effective at decreasing symptoms like depression, overeating, or chronic pain," Sandoz says, "but also that improvement happens by increasing flexibility."

I wish I could end here by reporting that I've just wrapped my scale up in plastic and hidden it in my basement, that I've now joined the ranks of the "intriguing 11 or 12 percent" who are satisfied with their bodies. But I'm afraid I'm not quite there yet. What if I'm not willing to let go of thin? What if embracing self-compassion means gaining 10 pounds? Am I trapped in food prison forever?

Sandoz offers this open-hearted response to my kvetching:

"You're never trapped. You have the keys to the prison! But sometimes having a choice is scarier than not having a choice. Sometimes the food prison is cozier than the big, wide world where I could bulge or break out or wrinkle at any moment. The question...is this: what is it worth, to you, letting yourself out of the prison? What matters more than that high? What matters more than thin? What do you want people to remember about the life you lived? Will you gain weight or lose weight? Yes. Will I gain weight or lose weight? Yup. Will we hate our bodies or love them? Sure. I just hope, for both of us, that we are doing things that matter while we're looking however we look and feeling however we feel.

And then she tells me a story: