Kaeli Madill is obsessed with dieting. She subscribes to magazines like Self, Shape and Runner's World for their "I-Lost-40-Pounds" success stories. She watches pound-shedding transformations on "The Biggest Loser." She flips through diet books, and buys those with glowing testimonials.

"It makes me feel like I can do it," said Madill, 26, who lives in Saskatchewan and is trying to lose 60 pounds. "If I get discouraged, I look at one of those stories, and say that person did it. That person had results, so in time, I'm going to have results, too."

These days, Madill has plenty of places to find inspiration. Personal weight-loss success stories are cropping up in magazines, on television, on blogs and in long-form memoirs, and seem to be resonating among the more than two-thirds of Americans who are overweight or obese.

Actress Valerie Bertinelli, who lost 40 pounds on Jenny Craig, was No. 1 on the Publishers Weekly best-seller nonfiction hardcover list last week for "Losing It: And Gaining My Life Back One Pound at a Time."

"Part of what draws you to a memoir is your ability to empathize and relate to these people and their lives," said Liz Perl, vice president and publisher of Rodale Books, whose many titles include "South Beach Diet" and "The Abs Diet."

"Clearly many Americans can empathize and relate to what it's like to lose control of your weight and your health."

While diet experts acknowledge the stories can be inspiring, they say reading and watching so many testimonials can also be problematic.

Kelly Brownell, director of the Rudd Center for Food Policy and Obesity at Yale, said he sees both opportunity and risk. The narratives may inspire people to shed pounds themselves — but the weight-loss techniques shown in books and elsewhere may not be nutritionally safe.

There is no "one size fits all" approach to weight loss, said Dr. Robert Kushner, medical director of diet.com's premium membership, who worries people may try to pattern themselves after the successful dieter.

"You can follow one program after another and none of it works for you," he said. "You can end up being more frustrated. There's no filtering (with these stories). There's no one saying, 'results vary, this may not work for you, read it with caution.' "

To their credit, some of the memoirs stay away from endorsing diet and exercise plans.

Susan Blech, who documents her 250 pound and counting weight loss in "Confessions of a Carb Queen," writes about her binge eating along with the Rice Diet Program she followed — where participants eat at "The Rice House" but don't center their diet on rice. She notes that some parts of the program did not work for her, and that she is not getting "monetarily paid" by the outpatient treatment center in Durham, N.C.

In "Hungry: Lessons Learned on the Journey from Fat to Thin," Allen Zadoff writes about his overeating as a part of a larger problem — an undiagnosed food addiction. And Jennette Fulda, author of the upcoming "Half-Assed: A Weight-Loss Memoir," writes that she doesn't want people to believe there is "one magic cure-all diet."

But many magazines do offer specific diet and exercise plans, along with details on how a person lost weight.

Most of this obsession stems from frustration, diet experts say. About 41 percent of Americans are trying to lose weight, according to a Consumer Reports telephone survey conducted last year. Most people who lose will regain. So when someone loses a large amount of weight, it's almost as though she has broken a code.

Yo-yo dieter Trista Blouin, 35, of Pensacola, Fla., has been dieting since she was 16. Her library of diet books dates back to Susan Powter.

"It's very discouraging," said Blouin, whose goal is to lose 70 pounds. When a new book comes out, "I think to myself, 'maybe this will be it.' "

Discouragement could be a byproduct of so many success stories focused on huge — and unusual — amounts of weight loss, Kushner said. He also took issue with shows like "The Biggest Loser," because they make weight loss a competition.

"I think that is the antithesis of what we are trying to convey as a healthcare community," said Kushner, also a professor at Northwestern University Feinberg School of Medicine. "Weight loss is not a game or a sport."

Most of the memoir authors say their goal was to inspire — not dish out dieting advice.

"I think whether it be Jenny Craig, Weight Watchers, whether it be any diet program, it's about building a community around you and leaning on your friends and your loved ones," Bertinelli said.

"I spent so much time going through all of the hardships thinking I was so alone," she added. "Had I just reached out, I would have realized I wasn't as alone as I thought I was."

Blech echoes that sentiment in her author's note: "I've written this book with my sister because for a long time, I felt very alone, and no one should feel that alone and scared and ashamed."

"This is a book that is not only going to help people but inspire them to want to live the kind of life they want to live," she said in an interview.

In the long run, it's clear that dieters need more than inspiration to be successful, said Judith Beck, author of "The Beck Diet Solution," which teaches cognitive techniques to help people stay on a diet, lose weight and maintain the weight loss. The inspiration may last days and even weeks, but what happens when dieting gets hard again?

"It's a bit like reading inspirational biographies of musicians," said Beck. "It might inspire you to learn how to play the piano or conduct the orchestra, but unless you learn the skills of how you do it, it's not going to matter very much."