Ensuring teenagers know exactly how overweight they are encourages them to adopt a healthier lifestyle, but in practice many fail to follow this through.

These are the findings of a study by PhD psychology student Julia Fredrickson, Dr Peter Kremer and Professor Marita McCabe from Deakin University, Australia that was presented on Thursday 8 May, at the British Psychological Society annual conference hosted at International Convention Centre, Birmingham.

Julia Fredrickson said: "Although overweight adolescents know they need to lose weight, they don't engage in healthy eating habits. This study aimed to examine the impact of weight perception and body change intentions on weight related behaviours in overweight adolescents."

Some 928 overweight adolescents between the ages of 11 and 18 completed a questionnaire focusing on perceived weight, satisfaction with weight, weight loss intention, muscle change intention as well as self-reported dietary intake and physical activity.

The relationship between weight perception, body change intention and behaviour was analysed.The results showed that although an accurate perception of being overweight was associated with the intention of losing weight, it did not affect their eating habits and was actually associated with less frequent physical activity.

Julia said: "Most overweight teenagers are aware they need to lose weight but, just like many adults, they fall short of actually making long term healthy changes to their lifestyle.

This feeling of failure can have negative repercussions for many teenagers and discourage them from adopting healthier habits. Interventions aimed at overweight teenagers should be considered carefully as it may not result in a healthy lifestyle change."