J. Lennert Veerman (Univ. Queensland) has a nice commentary out in the latest PLoS Medicine entitled On the Futility of Screening for Genes that Make You Fat. Like all papers in this journal, it is available full-text and open-access. There is no Abstract, but here is an excerpt that sets up the commentary:
There are at least four reasons why screening individuals for genes that predispose to obesity makes little clinical sense and may even do harm. Genetic screening for obesity has limited predictive power, is unlikely to inform therapeutic decisions, does not add to body mass index (BMI) as predictor of disease, and may distract from the societal changes that most experts think are needed to reduce the prevalence of obesity.
The commentary is highly recommended.