Obesity is rapidly becoming a global concern—18.5 percent of children aged 2 to 19 are considered obese in the United States, as are 20 percent of children aged 10 in the United Kingdom—but it has always been a personal issue for me. When I was a child growing up in a remote hamlet in Wales, everyone called it puppy fat, at first; but around age 11 or 12, the weight began to stick. I don’t really know why I got fat—my parents weren’t fat, we didn’t have cupboards full of sweets—but I remember that my world began to close in. I began to keep diaries in which I wrote about food, exercise, and my own feelings; I viewed everything through the prism of being overweight.

After I left home to attend university at 18, I eventually lost the weight, but I always felt that my body wasn’t good enough. Even though I looked slimmer, the feeling of being overweight stays with you, separating you from the rest of the world. The stigma of obesity follows the overweight throughout their lives—from the schoolyard to the workplace and beyond.

“You’re bombarded with the fact that you should be thin—on television, in films, in magazines, it’s everywhere. When you’re bigger you automatically think, What’s wrong with me?” — Sam, 17

As a documentary photographer, I’ve struggled with idea of doing a project about weight. Why am I not using the camera to document my own issues? I thought. The thing I know best? It wasn’t until I became pregnant at 33, and prepared to raise a young son, that I was ready to make work about childhood obesity. For the next eight years, I followed overweight children and teenagers in England and Wales as they went about their daily lives: spending time in their rooms, hanging out with friends, fretting about boys, preparing for prom. My youngest subject was 8 when I started speaking with her, and the oldest—whom I started shooting when she was 14—is now 21.

The most difficult aspect of the project, which I call “The Big O,” was getting introductions to my subjects. Few people wanted to present me to their friends’ overweight children; doctors wouldn’t introduce me because of patient confidentiality; and charities working with overweight children were reluctant, because they were sensitive to the feelings of kids who may not have wanted to be labeled fat—especially not by a photographer.

With time, I was given access to families by after-school clubs and weight-management organizations. Usually once I was able to sit down with a young person face-to-face and explain what I was doing with the project, they were happy to get involved. I think my subjects could feel that I’d been there. As we worked together, I showed all the photographs to the kids, to make sure they were happy with way I was depicting their lives.

Parents are mostly absent from my images, but their concerns for their children were always present. In 2014, when I was photographing one of the subjects, Sam, playing in a paddling pool, her dad turned to me. “She’s our daughter and we love her no matter what,” he said. “But she can’t afford to get any bigger.” My own father took a similar approach to my weight, kindly mishandling my emotions by offering money or rewards for weight loss. As a parent, saying anything about your child’s weight can come across as disapproving, but I know now that it comes from a place of love. When you’re a teenager, it’s hard to understand that.

What I also understand now—from talking to professionals who research childhood obesity, from spending time at fat camps and after-school clubs, from observing kids as they grow up, and from my own journey toward a healthy life—is that recovery isn’t about shame or rewards. It starts from within, with feeling good about yourself. As Shannon, one of first kids I photographed, wrote so eloquently in a poem: “Please don’t patronize me with ‘eat less and exercise more.’ Walk in my shoes for a day and then tell me what you think.”

“I feel more comfortable now than I used to because there are more overweight kids in my class than there used to be.” — Deana, 12