Middle-aged women who eat healthily for themselves have a lower body mass index than those who eat healthily to keep others happy, new research from Otago University shows.

The department of human nutrition study set out to examine the link between the degree of self-determination motivating women’s eating behaviour and their body weight.

The study involved 1600 women aged between 40 and 50.

Study co-author Dr Caroline Horwath says more self-determined reasons for eating healthily included enjoying creating healthy meals or viewing eating healthily as an important lifestyle choice.

However, other women reported feeling nagged to eat healthily or feeling expected to do so.

After adjusting for other potential explanatory factors, the results showed that the more self-determined or autonomous a woman’s style of motivation for eating healthily, the lower her BMI, Dr Horwath said.

“We found that controlled motivation to eat healthily was closely linked to more frequent binge-eating episodes,” she said.

“So interventions that improve women’s sense of autonomy could be useful in reducing unhealthy eating behaviours that may potentially lead to weight gain.”

The research appears in the September issue of the Journal of the Academy of Nutrition and Dietetics.