Here is an excerpt from an article discussing the damage to DNA caused by a high starch diet.
Genome-wide association studies this year provided insight into many diseases, including atrial fibrillation, autoimmune disease, bipolar disorder, breast cancer, colorectal cancer, type 1 and 2 diabetes, heart disease, hypertension, multiple sclerosis and rheumatoid arthritis.
In 2007, biologists also learned that within DNA's billions of bases, thousands to millions of them can get lost, added or copied in ways that can change genetic activity within a few generations. The effects of these "copy number variants" have been shown in populations with high-starch diets, as they have more copies of a gene for digesting starch than members of societies of hunter gatherers. Geneticists who studied the genomes of children with and without autism have found a new DNA modification that leads to increased risk for autism.