Experts say that your new blue jeans will expand by up to an inch and a half if you wear them a lot for several months. That can play out two ways: They may change to suit your shape, becoming more comfortable and making you look better; or, if not cared for, they can become out of shape and tattered.

Your genes can do the same thing — become positively reshaped because of smart daily habits (healthy food, consistent exercise, stress management, restful sleep), or change so that they fuel your risk for serious health problems.

Those changes in your genes involve switching them on or off, which is called epigenetics.

You can control about 80% of which genes are on or off by your lifestyle choices. And that can influence your cancer risk.

One study found that guys can turn off genes that increase their risk for prostate cancer by adopting an intensive nutritional upgrade, as well as not smoking, managing stress, and getting consistent exercise.

The same approaches reduce the risk for colon and breast cancers.

Another new study found that chronically unmanaged stress from poor physical and emotional lifestyle choices — such as lack of exercise, poor sleep, untreated depression/anxiety, and poor nutrition — causes a 28% increase in the risk of dying from cancer compared to someone the same age without chronically unmanaged stress.

Want help managing the genes that fuel a cancer-resistant, healthier you? Check out the program in my book "The Great Age Reboot."