I'm a lot lighter than I was last April -- a dramatic enough difference to get comments from people who haven't seen me for a while. Only one friend -- a nurse -- has thought to ask if I lost the weight on purpose. I did. So when everyone else goes straight to congratulations, I smile and say thank you. But there's more to the story of my new, slimmer self than simply feeling proud that my perseverance has paid off.

This is not the account of a miraculous makeover. I've always had a medium build. In the last few years, though, I'd slowly been putting on pounds, and quietly denying it. While my closet was crowded with clothes in my "official" size that no longer actually fit, I struggled to zip up larger-sized jeans, and hid my body under baggy tops. On forms, I filled in what my weight was "supposed" to be, and stopped stepping on the scale. If you don't know something, it's not happening.

But of course I did know. I'd even resolved to address the issue, and had stated my policy to my family: I was maintaining a healthy weight by exercising regularly, passing up second helpings, and avoiding between-meal snacks. Only I wasn't.

When no one was around, I ate all the time: when I was bored and when I was worried, when I was frustrated and when I was hungry. I always felt hungry -- even when my stomach already hurt from overeating. I learned that after a couple days of discomfort, my capacity expanded. I was eating so quickly and furtively that I hardly tasted what was going in my mouth.

The shame that accompanied this unauthorized ingestion increased when there were witnesses. At mealtimes, I dutifully took my sanctioned single helping but made sure it was plenty big. Then, telling myself I was making an "exception," I'd slink back to the stove for seconds, giving my husband a funny look. If you eat ironically, the calories don't count. At restaurants, I'd stare at the menu in panicked paralysis before settling on the most abstemious item -- the poached fish or grilled chicken breast. Then I'd go home and secretly scarf up more snacks.

All that changed last spring, when I went in for a routine checkup. Because I was 47, the lab work included my first-ever cholesterol count. The numbers weren't terrible, but they were trending in that direction. "You need to lose weight," my doctor told me. "You need to exercise more."

"I work out four times a week," I protested. That was only a slight exaggeration -- most weeks, I made it to the gym three times.

"Then you need to make it seven days," he replied, unimpressed.

I'd been cheating and denying, and had gotten caught. But he hadn't just uncovered a character flaw. He'd also issued a medical warning. And although the prognosis was hardly fatal, that's how I heard it. I knew firsthand that obesity significantly exacerbates health risks. My mother was obese, and it killed her.

She was fat before I was born. In my earliest baby pictures, I peer at the camera over the soft swell of her ample arm. When I was young, she never dieted or fretted aloud about her looks. Her weight was never even directly discussed. But it loomed as large as she did -- a defining aspect of her identity, and therefore of the whole family's. The party line wasn't that fat was bad. The world was, for discriminating against fat people.

The bias is most obvious in media imagery. But it's everywhere. My mother was reminded that society wasn't set up for her each time she tried to buy clothes, pass through a subway turnstile, slide into a diner booth, buckle a seatbelt or cover up with a hospital johnny. Anti-fat bigotry is the last taboo. Folks who would never dream of making cracks about a person's religion or sexual orientation or disability think nothing of snickering about somebody's size. Everyone knows the stereotype: Fat folks are stupid, lazy slobs.

By the time I was in grade school, I'd internalized the unfairness of such assumptions, and learned that those who held them were either mean or shallow. So what did it say about me that when my best friend made a crack about my mother's size, I wasn't just embarrassed for my mom, but by her? At a minimum, it put me in league with my mother's mother, whose insensitivity was legendary.

Childhood photos of my mother don't show a particularly plump girl. But that's how her slender, appearance-conscious mother viewed her. My grandmother kept a jar of pretzels in the dining room and forbade my mother to touch them. Mommy liked to tell the story of how she'd learned to lift the glass lid and extract the illicit treats without being overheard by her parents.

As Grandma got older, her prejudice became more pronounced. When she was in her nineties and my mother visited her, Grandma would point to passersby and make cracks like, "Look at that fat pig." Her comments baffled and galled my mother -- was she really that cruel, or just stunningly obtuse?

I was 41 when she died. And my own weight gain, which had begun slowly after I'd had children, started to accelerate. At first, I saw the trend as my natural inheritance. She and I were similar in so many ways, and I based lots of my actions on hers. I was always unconsciously asking, What would Mommy do? As I faced middle age, my destiny seemed clear. Like Mommy, I would get fat, suffer the societal and medical consequences of obesity, and die relatively young -- she lived to just 71.

Only I didn't want to die. So when my doctor seemed to confirm what I'd tacitly assumed, his assessment brought me up short. That afternoon, as his words sank in, I made a complete mental switch. Someone at my office had set out a communal plate of chocolate truffles. I started reaching for one, as I always did, but stopped myself. With a lurch of regret, I silently told the goodies, "We're through." I felt like a lover breaking off an affair.

I didn't pick up the latest diet or enroll in any program. The idea of using pills or dietary supplements never entered my mind. I would have three meals a day at regular times, mostly home-cooked and with family. I'd take reasonably sized portions, and no second helpings. I'd opt for fewer solid fats and more leafy vegetables. I'd step up my exercise regime. It was the same, straightforward approach I'd been claiming to be following. Only now I really meant it.

The first few days were miserable. All I could think about was how pitiful I was, and how famished. Before long, though, I realized that slightly empty was a better way to feel than over-stuffed. When the effort not to nosh became a distraction, I authorized for myself an afternoon snack every day. In an unconscious nod to my mother, I chose pretzels. I kept a bag in my drawer, and when my coworkers celebrated yet another birthday with yet another cake, I'd stay for the song and the candles, then return to my desk and crunch on a salty handful.

I aimed to reach my target weight by Rosh Hashanah, in October. To provide incentives, I set myself intermediate, 5-pound milestones -- how much I would weigh by my birthday, by my daughter's, by Labor Day. I wrote the numbers down in my date book, and started weighing myself each morning. The scale confirmed what I sensed. The pounds were coming off -- very quickly at first, and then more slowly. My jeans became baggier and baggier.

Sometime in the summer, I finally admitted my wardrobe didn't fit. Back in the winter, when I'd resigned myself to a future of steady weight gain, I'd finally given away the smaller clothes I'd worn in my twenties. Now I regretted the decision, and resigned myself to a different fate: having to buy new clothes.

For years I'd dreaded shopping, telling myself I had no use for fashion or the feminine beauty game. Now, picking clothes off the rack and trying them on turned out to be surprisingly pleasant. Zippers closed without effort. Shirts didn't strain at the bust. I went home with an armload of purchases.

Going out in my new, form-revealing clothes, I got my first taste of what it's like to draw compliments. It felt great, but also made me worry. Had I bought into the size-ist, anti-feminist mind-set? By determining I didn't have to be my mother, had I turned into my grandmother?

Another question was what to do with the old clothes. As always, I thought of Mommy. In the last decade of her life, her weight finally caught up with her. Faced with kidney failure, diabetes and heart disease, she struggled to lose pounds, only to put them on again. As her weight fluctuated, the closets in her home, by then empty of children, filled with clothes of different sizes. Nothing was discarded. She wasn't just a natural hoarder, but had also come to see her body as a constantly changing variable, like New England weather.

And, like the weather, she saw weight as a force of nature, not meant for human intervention. To act otherwise was hubris -- and sure to attract the evil eye. In deciding I was capable of taking control of my body, I was rejecting my mother's fatalism. But just to be on the safe side, I stashed my old, bigger clothes at the back of my closet.

I've stuck with my program for nine months so far. After I reached my "official" goal in October, I began working towards my secret target, which was 5 pounds less -- the amount I weighed 25 years ago, when I got married. I have my lighter days and my heavier days, but I've managed to stay between those two numbers since Thanksgiving. The daily step on the scale keeps me apprised -- and honest. No longer feeling like a liar may even be as valuable a pay-off as my lost pounds.

Have I let down the home team? Of course not. The legacy my mother left me isn't the fate of her body, but the insight of her experience. The understanding she taught me to extend to people built like her applies equally to those like me. What would Mommy do if she could see me now? That's easy to answer: She'd be as pleased as I am.