Live Science:

You are what you eat, the saying goes. And, according to two new genetic studies, you are what your mother, father, grandparents and great-grandparents ate, too.

Diet, be it poor or healthy, can so alter the nature of one's DNA that those changes can be passed on to the progeny. While this much has been speculated for years, researchers in two independent studies have found ways in which this likely is happening.

The findings, which involve epigenetics, may help explain the increased genetic risk that children face compared to their parents for diseases such as obesity and diabetes.

With that in mind, let's turn to a passage near the beginning of James Shapiro's short but dense masterpiece, Evolution: A View from the 21st Century:

In addition, the importance of short- and long-term transmission of so-called “epigenetic” information contained in complexes of DNA, RNA, and protein is a burgeoning field of contemporary research with important connections to the evolutionary process [9]. Beyond these few examples, we will undoubtedly discover new aspects of cell heredity in the coming decades. It is possible that DNA-based heredity will ultimately find a more modest role in our thinking about inheritance in the course of this new century.
This rethinking is of the greatest importance because, ultimately, social darwinism never really died. It was, instead, repackaged as genetic determinism and evolutionary psychology. We are now moving into a cultural climate that is much more open than one in which the neo-Darwinian synthesis was shaped.