New study asks why “willpower” alone fails the weight test

Lead researcher Lynette Mackey from QUT’s Institute of Health and Biomedical Innovation (IHBI) said the study was designed to determine if particular personality characteristics could be related to being overweight or obese.

“Food does provide a neurological signal of reward to the brain and those who are have a personality type that is sensitive to reward are more likely to eat tasty, sweet and fatty food simply because it is rewarding,” she said.

She said weight management programs encouraged the use of self-responsible behaviour and significant amounts of willpower by participants.

“We know there are people who struggle with their eating behaviour when they experience negative emotions,” she said.

“What we don’t know is which temperament factor is influencing the overeating behaviour the most.”

The PhD researcher said the ability to “stop and think” before acting was governed by a temperamental factor known as “effortful control”.

“We learn over time to approach things that are rewarding and to avoid things that are punishing purely in response to how we feel,” she said.

“Another part of temperament is being sensitive to punishment.

“To a person who is high in reward, the fear of missing out, the sting of frustration or the boredom inherent in doing something that is unstimulating creates potentially discomforting and punishing unrewarded states.

“My observation as a clinician suggests many clients failed their weight management attempts when they were busy, distracted, bored or discomforted or distressed in some way.”

She said a key question in the research was to determine to what extent the temperament type that was sensitive to punishment influenced the temperament type that was also sensitive to reward and if that influenced overeating behaviour.

“It makes intuitive sense that if someone is sensitive to the discomforting emotions that arise from temperament, then food, which is inherently rewarding may be used to improve mood,” Ms Mackey said.

She said initial results will be due next month.

The study participants involved nearly 200 non-smoking men and women aged between 18 – 65 with a body mass index of 25 or greater who do not suffer from an eating disorder.

To work out your BMI divide your current weight by your height (in metres squared).

Lynette Mackey is an accredited practising dietician and is undertaking the project as part of a PhD program.

The research is being overseen by Professor Neil King from QUT’s School of Exercise and Nutrition and Dr Melanie White from QUT’s School of Psychology and Counselling.

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Debra Nowland, QUT media officer (Mon/Wed/Thur), 07 3138 1150 or [email protected]