Are You Genetically Predisposed to Obesity?
You may not be doomed after all
Posted Jan 22, 2019
Does obesity run in your family? When you see pictures of yourself as an infant was there plenty of “baby fat?” As a child were you overweight? If you’ve used a genetic testing kit, did it reveal that your genes make it more likely that you’ll overeat, under exercise and gain weight? Especially if your parents and siblings were overweight and you were heavy as a child it’s natural to conclude that you’ve inherited a tendency to easily gain weight and losing it will be difficult or impossible.
There’s little doubt that genetics plays a role in determining how much you’ll weigh. Estimates from studies of identical vs. fraternal twins or studies comparing the weight of adoptees with that of their biological vs. adoptive parents suggest that, in general, genetics may determine anywhere between 30 to 70 percent of weight. Even if these findings were more precise they would describe the role of genetics in the population as a whole. We still wouldn’t know how much of your weight or my weight would be a result of our genetic make-up.
Recent research demonstrates that, although there are definite genes contributing to weight, these genes don’t have the final say over how much we’ll weigh. A Tulane University study found that healthy eating could reduce the role that genetics play in weight gain. In 1986 the researchers studied 14,000 male and female health professionals who had an average BMI of 26. They did a blood analysis of 77 genetic variants that have been linked to BMI. Every four years the participants’ BMI was calculated and they completed a 131-item food choice questionnaire. The quality of their diet was assessed based on the questionnaire responses.
As expected the researchers found a link between genetic risk score and increases in BMI every four years but, individuals who had maintained a healthy diet had the least increase in BMI. The lead researcher concluded, “…weight gain associated with genetic predisposition can be at least partly counteracted by improving adherence to healthy dietary patterns.”
These findings, as well as previous research, suggest that even if you have overweight parents and siblings or you were chubby as an infant or your genetic profile shows that you’re predisposed to easily gain weight all is not lost. It will probably be more difficult for you to maintain a healthy weight but your genes won’t doom you to lifelong obesity. A healthy diet can minimize the effects of heredity.
Wang, T., Heianza, Y., Sun, D. et al. Improving adherence to healthy dietary patterns, genetic risk, and long term weight gain: gene-diet interaction analysis in two prospective cohort studies. BMJ 2018;360:j5644