“At a time when high-calorie foods are aggressively marketed to us, it’s more important than ever to understand how genes influence BMI. We already know that these genes impact traits and behaviours such as hunger and emotional eating, but what makes this study different is that we tested the influence of two types of dietary restraint — rigid and flexible — on the effect of these behaviours. What we discovered for the first time was that increasing both types of restraint could potentially improve BMI in people genetically at risk; meaning that restraint-based interventions could be useful to target the problem,” said Psychology PhD student, Shahina Begum, from the University of Exeter who is also lead author of the study.
Currently, there are over 900 genes that have been identified and associated with BMI, several studies suggest that these risk genes influence one’s feelings of hunger and the loss of control towards food intake. Genes that are linked to obesity increase BMI, and up to a quarter of this effect is explained by increases in hunger and uncontrolled eating which includes emotional eating.
This study included 3,780 adults between the ages of 22-92 years old who were enrolled in the Genetics of Appetite Study and the Avon Longitudinal Study of Parents and Children. Participants had their weight and height measured as well as provided DNA samples via blood to calculate the overall score for their genetic risk of obesity. Participants also completed questionnaires to measure 13 eating behaviors which included disinhibition (binge or emotional eating) and overeating due to feelings of hunger.
Having a higher genetic risk score was found to be associated with a higher BMI which was partially due to hunger and disinhibition. Further analysis revealed that those who had high levels of dietary restraint reduced those effects by almost half for disinhibition and a third for hunger which suggests that restraint may counteract some of the effects of genetic risk.
There are several types of restraint ranging from flexible strategies in which one is conscious about what they eat and deliberately takes smaller servings, to rigid strategies in which one has to count all of the calories one eats to stay below a set caloric intake limit. The researchers tested the influence of these two types of restraint and found that they both could potentially improve BMI in those who are genetically at risk.
Interventions that could help to facilitate dietary restraint could include finding support, using a food tracking app, practicing portion control to reduce calorie intake, or creating a food journal to keep track of what is being consumed. To help people to learn how to change their food environment the members of the research team developed a Food Trainer App called FoodT which works as a game that trains the user to repeatedly stop high-calorie food intake, and their research suggests that this training may be particularly beneficial to those with a higher BMI.
Accompanying video: https://www.exeter.ac.uk/research/foodt/
