Our DNA is the very essence of who we are. It determines every feature and characteristic about us, ranging from hair and eye color to aptitude for math and science. In this day of plastic surgery mania, DNA is the one human feature that is virtually unchangeable. But recent research into the amazing field of epigenetics has suggested that that may not be completely true. Here are a few rather surprising ways that you can show Mother Nature who's boss and do the unthinkable: change your genetic makeup.

Before I further explain how training for a marathon or eating broccoli can change your genetic makeup, let’s first understand why it’s important for genes to have the ability to adapt in the first place. Genetic changes are necessary to life on Earth and enable us to adapt and thrive in our demanding environment. Epigenetics is a field of science which studies how our lifestyles and environments — and those of our ancestors — changed not the DNA sequence but rather how the cells “read” genes, LiveScience reported. By altering how the cells perceive genes, you change the physical structure of the DNA. It is through epigenetics that scientists are beginning to see that, as the saying goes, we really are what we eat. Although epigenetic changes are often temporary, it’s believed that in some cases it is possible to pass on epigenetic changes to future generations.

Exercise

While practice and training determine whether or not we hit our athletic peak, it’s up to our genes to set the bar of how high this peak may be. Unfortunately, this usually means that regardless of how many hours your put in on the track, Olympic runners are essentially born, not made. At least that’s what we thought. A recent study from Sweden found rather starting evidence to suggest that the genes you’re born with don’t necessarily limit your athletic abilities. According to the report, endurance training can physically change the skeletal muscle in our DNA, which affects both our health and muscle function.

The scientists involved in the study believe that the changes observed in the volunteers could be helpful for medical research. “This could be of great importance for the understanding and treatment of many common diseases such as diabetes and cardiovascular disease, but also for how to maintain a good muscle function throughout life,” explained lead investigator Carl Sundberg in a press release.

Diet

Researchers from Duke University found that the nutrients an organism consumed affected and changed the DNA of their offspring, according to a press release. The team compared how mouse clones implanted as embryos in separate mothers differed in fur color, weight, and risk for chronic disease based on what the mother was fed during pregnancy, and the results were quite fascinating. "Each nutrient, each interaction, each experience, can manifest itself through biochemical changes that ultimately dictate gene expression, whether at birth or 40 years down the road," concluded researcher Dr. Randy L. Jirtle.

A separate study found that these nutritional-based DNA changes also occurred in humans. It was also observed that nutrition affected even the sperm and egg cells, which means that these epigenetic changes could be passed on to offspring.

Trauma

Unfortunately, when it comes to nutrition, our genes remember both the good and the bad. One of the most fascinating and most well-documented cases of food affecting DNA occurred during the second World War. During the winter of 1944-1945, Nazi Germany blockaded towns across Western Netherlands, a period which become known as the Dutch Hongerwinter. This blockade resulted in massive food shortages and widespread starvation. As reported by The Telegraph, citizens trapped inside the blockade were forced to live off as little as 580 calories per day, and as a result over 22,000 people died from malnutrition.

Many decades later, scientific research found that the children born during this famine were underweight and more likely to suffer from disease. What was most startling, however, was that these children’s children were also born significantly underweight, despite never having experienced a nutritional scarcity during in vitro development. Researchers had concluded that the famine “scarred” the DNA of the victims, but it was only recently that we were able to correctly identify this “scarring” as epigenetics.

Mind

“I think, therefore I am.” If only Rene Descartes knew just how true this statement would turn out to be. While we know that the power of positive thinking can have amazing healing abilities, a recent study has suggested that positive thinking may actually affect our DNA. In a study led by Dr. Linda E. Carlson, mindful meditation, a type of Buddhist meditation was associated with preserving telomere length and increasing the lifespan of breast cancer patients.

Telomeres are essentially the “caps” to our chromosomes. They help to prevent our chromosomes from deteriorating, and poor health is associated with the caps shortening, Scientific American reported. Although telomeres naturally shorten with age, disease can cause this process to accelerate prematurely.

In the fascinating study, Carlson divided female breast cancer survivors into three types of therapy sessions: mindfulness meditation and yoga, group therapy, and finally stress management. Results showed that the women who partook in the meditation and the group therapy maintained the length of their telomeres, whereas the women who participated in the short stress management course did not.