The scientific reason your diet just won’t work

Photo: Nicolas Barbier Garreau

If you’ve already given up on a 2021 New Year’s resolution to start eating healthier or cut back on certain foods, don’t beat yourself up too much. A new study just released by King’s College London has collected compelling evidence that one’s diet is at least somewhat controlled or influenced by their genes. 

An individual’s genetics determine a whole lot. From hair color and facial structure to the risk of developing various diseases, our genetics “predetermine” much of our lives. While all of that is widely known and accepted, many will be shocked to hear that they are merely the co-authors of their grocery shopping lists. 

Much like many aspects of genetics, nothing is absolute when it comes to eating habits and diets. Your genes may predispose you toward certain food groups and flavors, but at the end of the day, we’re all still in control of our destinies. A strong determination to avoid the junk food aisle can overcome any genes that may be whispering in your ear that “one more bag of chips won’t do too much damage.”

“We know from previous twin studies that there is a strong genetic component for specific foods such as coffee and garlic, as well as overall eating habits. Our latest study is the first to show that food and nutrient intake, as measured by nine dietary indices, is also partly under genetic control,” explains first study author Olatz Mompeó-Masachs from King’s College London.

Researchers reached these conclusions through the use of “dietary indices.” These indices are just different categories or indexes of foods based on nutritional value. A group of 2,590 twins, some identical and some non-identical, filled out a series of dietary/food surveys. Then, the study authors used nine dietary indices to analyze their responses. 

Importantly, identical twins share an identical genetic profile. Non-identical twins, on the other hand, only share 50% of their genes. This difference is what allowed researchers to attain their findings.

Identical twins were found to be much more likely to share similar scores across the nine aforementioned dietary indexes. Notably, this held up even after researchers considered other factors like BMI or exercise habits. So, even if one twin is naturally lazier and the other twin hits the gym four days per week, both still tend to go for the same foods.

In summation, researchers argue that it’s tough to interpret these findings in any other way; genetics have at least somewhat of an impact on dietary choices.

“Our study represents the first comprehensive investigation of the contributions of genetic and environmental factors to the variation in eating behaviour. It highlights the complex relationship between genetics and environment and may have future implications for public health nutrition campaigns,” adds senior study author Dr. Massimo Mangino from King’s College London.

“This study used food data from female twins only, with an average age of 58. Future research will need to look at dietary indices across a more varied group of people to see if the same findings hold true,” he concludes.

Still, just the revelation that genes have any influence on nutritional dispositions and diet is a noteworthy finding. No one looks at dietary choices and eating habits the same way they view hair color or height. The notion that people aren’t entirely in control of their diets is sure to raise some eyebrows.

The full study can be found here, published in Twin Research and Human Genetics.