How dietary restraint could significantly reduce effects of genetic risk of obesity

Newswise — Genes associated with obesity increase appetite and diminish self-regulation of food intake, yet adopting dietary discipline can potentially offset these effects.

Recent findings from the University of Exeter, Exeter Clinical Research Facility, and University of Bristol, supported by the Medical Research Council Doctoral Training Partnership and published in the International Journal of Epidemiology, indicate that individuals with an elevated genetic predisposition to obesity can potentially mitigate the impact of hunger and uncontrolled eating by as much as 50% through the practice of dietary restraint.

Shahina Begum, a Psychology PhD student at the University of Exeter and the lead author of the study, emphasized the significance of understanding the role of genes in influencing BMI, particularly in a society where high-calorie foods are extensively marketed. The study distinguished itself by examining the impact of two forms of dietary restraint, namely rigid and flexible, on these behavioral traits. The novel finding revealed that augmenting both types of restraint may have the potential to enhance BMI outcomes in individuals with a genetic predisposition to obesity. This suggests that interventions focusing on restraint-based approaches could prove beneficial in addressing this issue.

Genetic factors associated with obesity contribute to higher body mass index (BMI), and approximately 25% of this effect can be attributed to heightened levels of hunger and uncontrolled eating, which encompasses emotional eating. Researchers have identified over 900 genes that are currently linked to BMI, and various studies indicate that these risk genes play a role in influencing sensations of hunger and the loss of control over food intake.

In this study, a total of 3,780 adults ranging in age from 22 to 92 years were recruited from two UK cohorts: the Genetics of Appetite Study and the Avon Longitudinal Study of Parents and Children. Participants' weight and height were measured, and a DNA sample was obtained from their blood to determine their overall genetic risk score for obesity. Additionally, they completed questionnaires that assessed various eating behaviors, including disinhibition (characterized by a tendency to engage in binge or emotional eating) and overeating in response to hunger.

Consistent with expectations, the study revealed that individuals with a higher genetic risk score exhibited elevated BMI, primarily attributable to heightened levels of disinhibition and hunger. Nevertheless, intriguingly, the findings demonstrated that individuals who practiced high levels of dietary restraint managed to mitigate these effects by almost 50% for disinhibition and one-third for hunger. These results suggest that the practice of dietary restraint may serve as a counteracting factor against the impacts of genetic risk in these areas.

The study investigated the impact of two distinct types of dietary restraint: flexible strategies, characterized by mindful food choices and portion control, and rigid strategies, involving strict calorie counting. Notably, this was the first study to examine the influence of both types of restraint simultaneously. The results indicated that both flexible and rigid dietary restraint approaches hold potential for improving BMI outcomes in individuals with a genetic predisposition to obesity.

Interventions aimed at promoting dietary restraint can incorporate strategies such as modifying the food environment to reduce calorie content or portion sizes. Additionally, providing support to individuals can be beneficial. Notably, the research team involved in the study has developed a Food Trainer app (available at https://www.exeter.ac.uk/research/foodt/) to facilitate this process. The app functions as a game that trains users to repeatedly resist high-calorie foods. Research suggests that this type of training may be particularly advantageous for individuals with a higher BMI.

The paper is entitled “Mediation and moderation of genetic risk to obesity through eating behaviours in two UK cohorts” and is published in the International Journal of Epidemiology.

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