In real life, dieting down to a smaller clothing size doesn't guarantee living happily ever after.
"Body dissatisfaction is a major risk for eating disorders in children all the way up through adulthood," she said.
Furthermore, role models like Maggie can perpetuate the idea that "if you don't look like Cinderella, you're a failure," Ikeda said. "I wouldn't want a child to read this ... because they might, in fact, try to do this and fail. What is that going to do to their self-esteem?"
Ikeda spoke to ABCNews.com without seeing the book.
She described Kramer's response to the public health perils of pediatric obesity as "well-intentioned but very misguided. It reminds me of the old saying 'fools rush in where angels fear to tread.' It's unfortunate that he didn't consult with people experienced in treating pediatric overweight."
Nutritionists and pediatricians today encourage overweight youngsters to eat a good, balanced diet and exercise regularly, rather than become caught up in weight-loss plans.
The idea that a child of 6 to 10 might read a book about dieting and try to emulate the main character runs counter to the policies of mainstream plans like Weight Watchers. Weight Watchers excludes from its weekly meetings any children under the age of 10, and only admits those 10 to 16 "with a doctor's note identifying the weight goal for the child."
Youngsters must be at least 13 to participate in Weight Watchers' newer online program.
For boys and girls who haven't yet passed through puberty, cutting calories poses "the danger of stunting growth and height," Ikeda said. "As a consequence, most responsible health professionals would not recommend dieting, even for overweight children. There's usually the strategy of trying to help children grow into their weight."
Pediatric obesity literature contains cases "where children restricted their calorie intake because they were so afraid of becoming fat that they actually slowed down their growth curve," she said. In addition, some researchers have reported that dieting among teenage girls "leads to greater risk of overweight than among girls who don't diet during their teenage years."
In her own study of women carrying around hundreds of extra pounds, Ikeda found that the heaviest among them "had actually started dieting before they were 13."
Extreme weight fluctuations from years of yo-yo dieting can be downright dangerous, Ikeda said, and "contribute to increased risk of obesity, coronary heart disease and hypertension."
Kramer argues that people are judging a book by its cover instead of waiting to read the book when it comes out.