Feces collected from genetically modified fruit flies may help researchers explain why pregnant women experience bloating and constipation, as well as pointing to an association between calorie absorption and lifespan.

A study published in the journal Cell Metabolism found that fruit flies, whose intestinal neurons are very similar to those of humans, have difficulty with constipation and retain more water when pregnant than at other times.

By analyzing samples of their feces, researchers discovered that these issues are caused by a compound, called the sex peptide, that male flies deposit into females during mating. The peptide causes its gut nerves to absorb more nutrients and water, leading to irregular bowel movements.

The study’s authors wrote that this process, which is caused by sex hormones in human females, may be an evolutionary response. Slowing digestion and absorbing more food and nutrients likely helps a pregnant female feed its growing young more efficiently. The process may also kick in during periods of food deprivation, the team added.

However, unproductive constipation in humans can also cause health problems. The study advised that men and women alike watch what they eat to avoid irregularity.