With a swab of saliva and a swipe of a credit card, countless health-conscious consumers are paying top dollar to discover what microscopic evils lurk in their genes. Among the many mail-order DNA tests available online is a "nutrigenomic" exam, which promises -- for US$395 -- to uncover how a person responds to certain foods. The end result, the companies claim, is a personalized diet plan tailored for you and your one-of-a-kind DNA. In the second instalment of a three-part series, National Post reporter Michael Friscolanti finds out whether his genes are the reason he's having trouble fitting into his jeans.

In a few short weeks, a sliver of my DNA went from the inside of my cheek to a mailbox around the corner to a Seattle-bound plane to a small laboratory I have never seen.

Find out more about the DNA diet at http://www.canada.com.