Children's movies are sending out mixed, and often unhealthy, messages about nutrition and weight, a new study has found.

US researchers looked at the highest grossing children's movies that had been released between 2006 and 2010. Four movies per year were analysed, amounting to a total of 20. Segments from movies such as Kung Fu Panda and Shrek the Third were assessed.

The study found that there were twice as many ‘unhealthy' movie segments as ‘healthy' segments and almost three in four of the films included content that stigmatised weight. For example, in Kung Fu Panda, the panda that wants to be a martial arts master is told he will not achieve this because of his ‘fat butt', ‘ridiculous belly' and ‘flabby arms'.

When it came to eating behaviours, one in four of the segments that featured food showed exaggerated portion sizes, one in five showed sugar-sweetened beverages and just over half showed unhealthy snacks.

Many of the movie segments also showed characters undertaking sedentary behaviours, such as watching television and playing video games.

"These children's movies offer a discordant presentation about food, exercise and weight status, glamourising unhealthy eating and sedentary behaviour, yet condemning obesity itself," explained Dr Eliana Perrin of the University of North Carolina.

The researchers concluded that these movies ‘present a mixed message to children - promoting unhealthy behaviours while stigmatising the behaviours' possible effects'.

Details of these findings are published in the journal, Obesity.