Would you still go to the local fast food joint for dinner if I told you that it might shorten the lives of your children?
Evolution has shaped human behavior over millions of years, and generally speaking it has done a pretty good job... But not a perfect one. Have you ever been about to fall asleep, only to have your whole body twitch violently, waking you up? That is because when your breathing rate gets too low your brain thinks you are dying and sends a shock through your nervous system to speed things up again. Another notorious, and far more damaging, quirk is the fact that when we taste something that is really fatty, salty, or sweet we want to cram as much of it into our faces as we possibly can.
The reason for this is that evolution is incredibly short-sighted. Before civilization fatty, salty, and sweet foods were pretty hard to come by. Since your body needs fat, salt, and sugars to survive it has evolved to instinctively load up on them whenever they are available. It’s a built-in nutritional reservoir that anticipates long stretches between solid meals.
This only becomes a problem when you have a pizzeria on every corner or a burger place every two blocks. Unfortunately, most places in the developed world are molding themselves into that perfect picture of gluttony.
We all know eating too much of that stuff is a bad idea. We know we will get fat, have high blood-pressure and diabetes, and probably die sooner. What most people don’t realize, and science is only beginning to understand, is that the consequences of poor diet might continue long after we are cozy in our jumbo-sized caskets.
Research in the growing field of Epigenetics has shown that environmental factors like diet, exercise, and air quality can change the DNA that people pass on to their kids and that their kids pass on to their grandkids.
It sounds a little crazy. DNA is supposed to be this engrained and unchangeable part of who we are. Then again, maybe not…
When we eat poorly and don’t exercise, our body adapts to that. Apparently that adaptation goes all the way down to our genes. The mechanism is called a “Methyl Tag.” Methyl tags are molecules that are produced by the body in response to those pesky environmental factors. Once produced, they bind with – and ultimately screw with – DNA. Some methyl tags can cover up pieces of your genetic code, making them inactive. Others do the opposite and highlight pieces that were just minding their own business.
The process is complex and not yet completely understood, but there is strong evidence that these changes can have lasting, inheritable effects on a person’s bloodline. One study demonstrated that mothers who were in New York on September 11, 2001 gave birth to babies with higher levels of stress hormones than mothers living elsewhere. Basically, their babies were born with post-traumatic stress disorder. Another bit of research looked at the grandchildren of people who lived through periods of extreme famine during WWII and found that their lifespans were significantly shortened. It has likewise been suggested that a person who lazes about all day and eats nothing but junk food will have children who are predisposed to obesity.
Experimental evidence has shown that methyl tags stick around. Fruit flies continue to show the effects of environmental pressure for 500 generations… But that’s largely because a fruit fly generation lasts about as long as it will take you to read this article. Since human lifecycles last so much longer and we have so few children (compared to flies), the current belief is that our own methyl tags probably affect our bloodline for 3 generations.
It’s a lot of responsibility to take on; knowing that eating a cheeseburger instead of a salad might make your grandkids unhealthy. On the other hand, it gives you even more reason to make responsible choices. By not smoking and exercising regularly you are not only being good to yourself, you are – in a real sense – a hero to future generations. That’s definitely something to keep in mind the next time you are tempted by that extra slice of chocolate cake.