José M. Ordovás
Senior scientist and scientific advisor at the Jean Mayer USDA Human Nutrition Research Center on Aging and professor at the Gerald J and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University.
Rather than changing our view of obesity, this study reinforces it. The rise in obesity is not explained by recent genetic changes, but by environmental changes that disproportionately affect those with a greater genetic susceptibility.
Or, to put it another way, I wouldn't call it an unexpected finding, but rather a good confirmation with cohort data. Obesity has increased too rapidly to be attributed solely to genes, but the current environment may be making genetic predisposition more significant.
The clear limitation is that it doesn't identify which specific environmental components are responsible for the increase and for this interaction with genes.