It’s no secret that different people have different responses to food intake.

By ingesting a single piece of bread, different people will respond with a blood sugar rise ranging from 10% to 100%. The reason we are individually different is part how we are wired, part how we behave, part how we have behaved in the past, and even part how our ancestors behaved.

Of course everyone has different absorption and metabolic machinery that helps determine their unique response to food. But consider the following three facts about the average person’s health in the United States. No matter your body’s response to food, the truth is universal: what you eat is far more important than you think.

Just 100 calories
Suppose you take the average person and he or she consumes 100 extra calories per day over what he or she actually needs. After a full year of this behavior, he or she has consumed 35,000 excess calories. That is equivalent to 10 extra pounds each year. Keep that up for a full 10–15 years, and this person will certainly have a problem on their hands.

But what’s in 100 calories? The answer: not very much. 100 calories is merely 10 peanut M&Ms or roughly one package of Reese’s Peanut Butter Cups. It’s 1/2 to 1/3 of a bagel with nothing on it or one half of a small, 8-ounce latte.

Sure, individuals have mitigating factors that affect how their body responds to this extra intake, but simple truth is that these seemingly insignificant overages accumulate over time to have dramatic effects.

Your genes are your genes… or are they?
Many people believe that the consequences of their food intake will be seen exclusively around their waistline. Unfortunately, that’s not so. Our behavior with food—how much we eat, what we eat, and what we’re exposed to through eating—actually affects how our genetic code functions.

You may have thought your genes were your genes. That has been one of the solid parts of science you could always rely on. As it turns out, that’s not the case. From even before you were born, what your genes tell your body to do is being constantly modified by what we eat, toxins we’re exposed to, stresses we have, caloric excess or caloric deprivation. All these factors affect how our DNA functions now and well into the rest of our lives.

The recent study of this activity has raised the profile of a field called epigenetics. Research in this field seeks to explain how things outside your chromosomes directly affect how your chromosomes function, your body’s metabolism, and your risk for chronic diseases.

For generations to come
As you can now see, it takes very little to spark dramatic change in not only our bodies, but our genetic makeup. While your genes don’t change their structure, their function changes immensely by the result of your behaviors, and it isn’t only you who is affected. The food we are exposed to can modify gene function for your subsequent generations.

No, I am not mistaken. Studies have shown that a certain portion of these controlling factors go with the sperm and the egg when forming a new individual. In humans these effects have been shown to pass on at least three generations, and in plants over 100 generations.

The seemingly small decisions that we make each and every day on how much we eat, what we eat, and what we expose our bodies to not only affects the very core signature DNA of our being, it does so for generations to come.

These truths may not set you free, but they should at least set your mind spinning and your chromosomes twisting.

Jeff Thompson, MD, is a speaker, pediatrician, chief executive officer emeritus at Gundersen Health System, and author of Lead True with ForbesBooks. Learn more at This post was originally featured on