‘Dietary restraint outsmarts obesity risk genes‘ – Written by Charlotte Harrison, Science Writer
Genetic variation underlies 40–70% of differences in body mass index (BMI) between individuals. And because many obesity risk genes are found in brain pathways that modulate reward, hunger and satiety, people with these risk genes can feel hungrier and lose control over their eating. New research led by the University of Exeter indicates that people can counteract the effect of obesity risk genes through dietary restraint.
Rigid and flexible restraint
Unlike previous studies, the current study tested the influence of two types of dietary restraint — rigid and flexible — on the effect of hunger and emotional eating. Flexible strategies include being conscious about what type and how much food is eaten, whereas rigid strategies include calorie counting. The study found that increasing both types of restraint might improve BMI in people genetically at risk.
The authors examined data from 3,780 adults aged 22–92 years. The data included questionnaire-based measures of eating behaviours, including over-eating due to hunger and a person’s tendency to binge or emotionally eat. In addition, as well as BMI, a person’s genetic risk score was documented; this was calculated from their genetic data such as BMI-related single nucleotide polymorphisms.
As expected, the researchers found that a higher genetic risk score was associated with a higher BMI. This was partly due to increased hunger-based eating as well as binge and emotional eating. Moreover, the findings showed that people who had high levels of dietary restraint reduced the effect of genetics on BMI – by almost half for binge and emotional eating and a third for hunger-driven eating.
Overall, the researchers found that restraining overeating that was due to habit had the largest counteracting effect on obesity risk genes. The authors suggest this is because there are many opportunities for habitual overeating in everyday life, such as large portions and easy availability of snacks.
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