Gene-environment interaction (GxE) refers to the dynamic relationship between an individual’s genetic makeup and physical and social environment. This interaction factors into what determines how a person’s genes are expressed, influencing traits, diseases, and overall genetic expression. (1)
Recently, nutrition coach and health author Thomas DeLauer illustrated the concept of GxE by examining cases of obesity in twins raised in different environments.
“Separated twins — two people with the same DNA — put into two completely separate environments. How do they fare against obesity? Does one become obese and the other not solely because of their environment?” DeLauer questioned.
[Related: What Should You Drink to Stay Legit Hydrated]
Twin Obesity Research
A New England Journal of Medicine study examined twins with genetic mutations linked to obesity. The findings reveal that, regardless of environmental factors, these individuals were predisposed to gaining weight and becoming obese. This genetic influence accounted for 69% of cases in women and 74% in men. (2) Dealing with obesity genes presents significant challenges, making it difficult to avoid obesity even in favorable environments.
However, if identical twins are placed in an environment that promotes unhealthy eating and encourages obesity, their chances of becoming obese could approach nearly 100%.
When addressing individual fitness, the influence of hereditary obesity genes cannot be overlooked. A study published in Frontiers in Endocrinology highlights that the presence of these genes gives a child a 47% to 91% likelihood of developing an obesity-related gene mutation. (3)
Whether children inherit these genes or not, they’re highly likely to grow up in an environment filled with unhealthy, processed foods. This can trigger epigenetic changes and environmental factors that significantly increase the risk of obesity.
Gene-Environment Interaction
The human genome evolves slowly. “100 years ago, we were pretty lean as a society,” DeLauer suggested.
Today, American society faces rising obesity rates, with many individuals classified as overweight. Nearly 43% of Americans are classified as obese. It’s unlikely that genetic makeup has changed significantly in 100 years, as DNA evolves over a much longer timescale. According to DeLauer, it’s not our DNA changing; it’s our environment. The genetic predispositions for obesity likely existed a century ago, but the environmental triggers to activate them were far less prevalent.
“We didn’t have food readily available. We have an opposite problem today,” DeLauer explained. “100 years ago, it was harder to get food. Nowadays, food is everywhere. We have a crisis-of-abundance issue, not a crisis of needing food.”
Someone carrying the obesity gene placed in a controlled metabolic ward with restricted calorie intake will not become obese. However, in an unrestricted environment where they can eat freely, the likelihood of obesity increases significantly.
Control Environment
According to DeLauer, small, unglamorous actions often make the most sense. Although these hacks may seem insignificant, they can collectively address more significant challenges. Some of the ways to control one’s environment to help prevent obesity include:
- Avoid having access to unhealthy food where you live.
- Intermittent fasting involves setting specific eating and fasting periods. Establishing boundaries for when and what to eat is efficient for individuals with obesity-prone genetics.
- Move more daily. While a sedentary lifestyle can negate the benefits of exercise, incorporating regular activity throughout the day can help maintain metabolic health.
- Consider compressing eating windows to regulate calorie intake and metabolism.
Environment and lifestyle significantly affect body composition and mood. Strive to live in a way that supports your overall health and well-being.
More In Research
- Do Artificial Sweeteners Impact Diet Quality?
- The Impact of Diet and Training on Your Bones
- 4 Studies to Determine the Best Biceps Exercise
References
- Ottman R. (1996). Gene-environment interaction: definitions and study designs. Preventive medicine, 25(6), 764–770. https://doi.org/10.1006/pmed.1996.0117
- Stunkard, A. J., Harris, J. R., Pedersen, N. L., & McClearn, G. E. (1990). The body-mass index of twins who have been reared apart. The New England journal of medicine, 322(21), 1483–1487. https://doi.org/10.1056/NEJM199005243222102
- Elks, C. E., den Hoed, M., Zhao, J. H., Sharp, S. J., Wareham, N. J., Loos, R. J., & Ong, K. K. (2012). Variability in the heritability of body mass index: a systematic review and meta-regression. Frontiers in endocrinology, 3, 29. https://doi.org/10.3389/fendo.2012.00029
Featured image via Shutterstock/Andrew Goodsell
