Men with a high-sugar diet are more likely to have obese children, according to a recent study involving fruit flies.

An international team of researchers found that that increasing sugar in the diet of male fruit flies for just 1 or 2 days before mating can cause obesity in their offspring through alterations that affect gene expression in the embryo. The study provides insights into how certain metabolic traits are inherited and may help investigators determine whether they can be altered.

Through mating experiments in Drosophila melanogaster, or fruit flies, the scientists found that dietary interventions in males could change the body composition of offspring, with increased sugar leading to obesity in the next generation. High dietary sugar increased gene expression through epigenetic changes, which affect gene activity without changing the DNA's underlying sequence.

"To use computer terms, if our genes are the hardware, our epigenetics is the software that decides how the hardware is used," researcher Anita Öst explained. "It turns out that the father's diet reprograms the epigenetic 'software' so that genes needed for fat production are turned on in their sons."

Because epigenetic programs are somewhat plastic, the investigators suspect that it might be possible to reprogram obese epigenetic programs to lean epigenetic programs.

"At the moment, we and other researchers are manipulating the epigenetics in early life, but we don't know if it is possible to rewrite an adult program," Öst explained.

The fruit fly models and experiments that the team designed will be valuable resources for the scientific community. Because the flies reproduce quickly, they can allow investigators to quickly map out the details of how nutrition and other environmental stimuli affect epigenetics and whether or not they can be modulated, both early and later in life.

The findings are detailed in the Cell Press journal Cell.