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Eating Habits Partially Connected to Your Genetics, Study Finds

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Key Takeaways

  • A study of twins suggests there may be a genetic component to eating habits.
  • Identical twin pairs were more likely to have similar scores across nine dietary indices, compared to non-identical twins.
  • While the research is interesting, experts say control of food intake patterns is under the influence of numerous other factors, including emotional, sensory, and environmental influences.

It’s no surprise that our dietary choices are influenced by external factors, like what’s put on our plates when we’re growing up, and what media messages we’re exposed to as adults. But new research from a team at King’s College London, published in the journal Twin Research and Human Genetics, suggests that genetics also play a part.

A Closer Look at the Study

Using a type of analysis called "dietary indices" to understand what foods someone eats and the nutrients they get from them, compared with recommended guidelines, researchers can determine the quality of someone’s typical diet.

In this case, the researchers analyzed questionnaires completed by 2,590 twins, using nine commonly used dietary indices. They looked at how similar the scores were among identical twins (who share 100% of their genes) versus non-identical twins (who share 50% of their genes).

The analysis found that identical twin pairs were more likely to have similar scores across the nine dietary indices, compared with their non-identical twin counterparts. And the results weren’t affected by other factors, such as body mass index (BMI) and exercise habits—suggesting that there’s a genetic component to eating habits.

The study authors say their research is the first to show that food and nutrient intake, as measured by the nine dietary indices, is also partly under genetic control.

Julie Miller Jones, PhD, LN, CNS, RD

The control of food intake patterns is under the influence of numerous factors including epigenetic, emotional, sensory, and environmental influences.

— Julie Miller Jones, PhD, LN, CNS, RD

"In this study, we utilized the classical twin approach and analyzed the correlation of the diet between similar (monozygotic) and dissimilar (dizygotic) twins," says lead author Dr. Massimo Mangino.

"If the correlation between monozygotic twins is higher that the correlation between dizygotic twins then you have an evidence that the analyzed trait (in this case diet) has a genetic component," Dr. Mangino explains. "We observed that all the dietary patterns are influenced by a genetic component. This component is stronger for some diets and less profound—but still detectable—in others."

The study has its limitations—it used food data from female twins only, with an average age of 58—and future research will need to look at dietary indices across a more varied group of people to see if the same findings hold true. But it certainly highlights the complex relationship between genetics and environment, and may have future implications for public health nutrition campaigns.

What the Experts Say

We're still researching the extent to which our food intake patterns are under genetic control, says Vanessa Rissetto, MS, RD, CDN, co-founder of Culina Health. She points to recent Canadian guidelines that indicate obesity to be a chronic disease, and show that people who are struggling with their weight might be genetically predisposed.

If the study shows that our food intake patterns are partly under genetic control, the important word is "partly," says Julie Miller Jones, PhD, LN, CNS, RD, an emeritus professor of nutrition at St. Catherine University in St. Paul, MN, and a member of the Grain Foods Foundation's Scientific Advisory Board. She points to another study of twins adopted by different families and reared apart, which showed that their BMIs were more like their biological parents than adoptive parents.

"The control of food intake patterns is under the influence of numerous factors including epigenetic, emotional, sensory, and environmental influences," she explains. "Stress, depression, sadness, food offerings and/or choices (including affordability), and cultural or familiar food practices also influence choices."

Vanessa Rissetto, MS, RD, CDN

If you grew up only eating fast food and no one ever gave you a fruit or a vegetable, it's going to be hard to start eating spinach and broccoli daily. We have to consider exposure to be an important factor, and not just availability.

— Vanessa Rissetto, MS, RD, CDN

Early feeding difficulties and pressure to eat may impact pickiness, which can also affect eating patterns, Miller Jones adds. This is particularly so if the mother seems very worried about eating behaviors. "Types of food offered, such as fruit, and eating with the child (versus ready-prepared food or special foods for the child) affects pickiness and eating patterns," she says.

Rissetto agrees that the types of foods kids are exposed to growing up is significant. "If you grew up only eating fast food and no one ever gave you a fruit or a vegetable, it's going to be hard to start eating spinach and broccoli daily," she says. "We have to consider exposure to be an important factor, and not just availability."

With all of this in mind, Miller Jones says she hopes all families model healthy eating patterns that include all the food groups, such as the Mediterranean or Flexitarian diets.

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  1. Mompeo O, et al. Genetic and Environmental Influences of Dietary Indices in a UK Female Twin Cohort. Twin Research and Human Genetics. 2021 Jan. doi:10.1017/thg.2020.84

  2. Wharton S, et al. Obesity in adults: a clinical practice guideline. CMAJ. 2020 Aug. doi: 10.1503/cmaj.191707