Your genes don’t tell your story—what is between them does. Your genetic make-up is a little like being given a car that you didn’t get to choose. Your genes might determine what kind of car you get, its quality and some of its specific features. All cars have a steering wheel, four tires, an engine, brakes and so on, while humans have two eyes, a nose, two arms, two legs and so on. But after you get the car, whether you turn right or left, where you take it, what you put in it, and how you treat it will largely determine how long it lasts and how well it performs.

Similarly, our health outcomes are determined by our actions, which serve as triggers to turn some genes on or off, far more than some inevitable script written by our genes from birth.

When scientists began mapping the human genome, many believed that we would soon be able to map—and thus control—many aspects of human genetics. However, as is usually the case when it comes to human physiology and scientific hubris, the reality is more complex and the truth far more nuanced.

Epigenetics—which translates to upon the gene—is the study of how our behavior affects our genes. The majority of obesity we see today does not come from genetic determinism or mutations, as previously thought, but rather from harmful environmental factors that force good genes to behave badly by switching them on and off at the wrong time.

Obesity runs in my family. Many of us have struggled with it—my father died from it, weighing 424 pounds at the time of his death. My mother once weighed 370 pounds, and I’ve had other relatives get bariatric surgery or other obesity-related stomach surgeries. This is a common story, leading to many to feel hopeless due to mistaken belief that the obesity outcome is inalterable.

Dutch Hunger Winter

Toward the end of WWII in 1944-1945, an unusually harsh winter combined with a German-imposed food embargo led to death by starvation of some 30,000 people in the Netherlands. This time period has become known as the “Dutch Hunger Winter.” Those who survived suffered from a range of developmental and adult disorders, including low birth weight, diabetes, obesity, coronary heart disease, and breast and other cancers. More importantly, Dutch researchers have associated these changes with the health of the grandchildren of people who conceived children during this “hunger winter.”

This remarkable finding suggests the effects of a pregnant woman’s diet can be felt into at least the next two generations. It has been theorized that genetic markers had been turned on in fetuses conceived during this winter, which allowed them to get the most out of the limited amount of food available. In a single generation, the physical environment altered gene expression. This is a rather powerful example of how turning the right genes on and the wrong ones off can make all the difference to health.

Choices

For children born during the Dutch Hunger Winter—and for me and my family—choices become even more important than for those who are not affected by epigenetic tags that have been switched on to enhance biological efficiency. I’ve pursued a healthy life and successful fitness career. Interestingly, an old friend from high school saw me recently and said, “Age has been kind to you.” To which I replied, “No it hasn’t. Choices have.”

Food Isn’t Fuel—It’s a Language

As Catherine Shanahan so eloquently puts it in Deep Nutrition: “Our genes make their day-to-day decisions based on chemical information they receive from the food we eat, information encoded in our food and carried from that food item’s original source, a microenvironment of land or sea…food is less like a fuel and more like a language conveying information.”

Many of our genes—just like our cars—can go left or right. And the daily, moment-to-moment choices we make provide the steering toward or away from health.

Exercise and Obesity

One of the more commonly repeated errors and mistaken beliefs regarding obesity is that exercise plays little to no role in weight loss. Actually, exercise works in at least three ways to manage obesity:

(1) It increases insulin sensitivity, so you need less insulin to get sugar out of your bloodstream. This allows your insulin levels to drop, which tells your fat cells to slow down the conversion of sugar into more fat.

(2) It reduces cortisol, which packs fat around organs, where it produces pro-inflammatory chemicals, which in turn tell the body to produce still more fat.

(3) Exercise makes blood sugar levels drop by forcing sugar into muscle cells for use as energy, so it reduces the sugar-induced inflammation that blocks healthy bodybuilding signals.

These aren’t debatable—this is what happens to human bodies in response to exercise. If you just restrict calories and never exercise properly, your fat tissues never receive the chemical message that more cells are needed in another department, and so the fat cells stay put. Calorie restriction without exercise tells your body to convert stem cells into fat cells as soon as you start eating again.

Gene School

Our lifestyles teach our genes how to behave. You aren’t “just big-boned.” Having a family history of obesity means simply that some of the genes that promote obesity may have learned to be more active due to the choices made by those in your family who came before you. However, you can teach those genes to be less active by taking more control of your choices. This is a message of hope to anyone struggling with obesity that your actions do in fact create reactions in your body.