Gastric bypass surgery is efficient at reducing the body weight of individuals in a very short span.

When the investigators probed deeper, they found that weight loss after surgery causes changes in DNA modifications that control gene expression in response to the environment. Specifically, changes in methylation, or chemical markings, on two genes that control glucose and fat metabolism (called PGC-1alpha and PDK4) correlate with obesity but are reversed after surgery-induced weight loss. The findings suggest that the environment—in this case food intake or weight loss—can affect gene expression through this mechanism.
"The novelty of our work originates with the finding that DNA methylation is altered by weight loss." says first author Romain Barrès, of the University of Copenhagen, in Denmark.
The findings may be useful for the design of new drugs that mimic this weight-loss-associated control of gene regulation.