The cover of the book, titled Maggie Goes on a Diet, has an illustration of a podgy girl holding a dress (a few sizes too small) while staring in the mirror and seeing a reflection of a slimmer, happier self.

According to the synopsis, the book is about "a 14-year-old girl who goes on a diet and is transformed from being extremely overweight and insecure to a normal-sized girl who becomes the school soccer star".

"Through time, exercise and hard work, Maggie becomes more and more confident and develops a positive self-image," the synopsis continues.

The 44-page book was self-published by an American author and father, Paul M Kramer, who said it was meant to be read by parents with their children aged six to 12 years.

Parents, nutritionists and online commentators all agreed that child obesity is a weighty issue that needs to be dealt with (especially in the US, where 16% to 33% of children and teens are obese).

However, some were worried that this book might feed negative body image issues. Some critics were furious that an author who had no expertise in health had written a diet book aimed at children.

Others argued that, if the book was aimed at promoting nutrition and fitness, it wouldn't use the word "diet" in its title or an image of a big girl dreaming of wearing a sleeveless, low-cut dress on its cover.

Kram er responded to critics on Fox News , stating his book tackled the issues kids faced.

He said: "I'm not advocating, and never have , that any child should go on a diet.

"First of all, this is [about] a change of lifestyle."

He even responded to critics who had complained about the story's cause-effect relation between losing weight and gaining popularity, and refuted claims that his book promoted weight loss as a means of being happier and prettier as opposed to being healthier.

"If one is obese, and one loses a bunch of weight, and one becomes fit, I think the rewards of just accomplishing that are good enough," said Kramer.

The book has its defenders who believe it offers sensible advice that could help combat child obesity.

Dr Keith Ablow of Fox News described Maggie as "a welcome truth-seeker", adding "she's a fabulous role model, far better than the size 20 women who go on talk shows and lie about how happy they are with their bodies".