As if there were not already enough concern about the impact of GMO crops on agriculture and the environment, a new international study raises the worry that a diet including genetically modified ingredients may be contributing to obesity.

The effect of GM foods on rats, mice, pig and salmon is being studied by an international team from Hungary, Austria, Ireland, Turkey, Australia and Norway. In March they reported preliminary findings that found no negative metabolic changes in the pigs, salmon or mice they tested.

The results released in July link GM corn with modest weight gain in rats. The animals were fed corn with an insect-resistant gene. The control group ate unmodified corn. During the course of the 90-day study, the gm-fed rats gained more weight than the others.

Professor Ã…shild Krog Dahl cautions more study is needed but that if the impact on humans is similar, long-term consumption of genetically modified food or the meat from animals fed a GM diet could be contributing to the increase in obesity.

Although the study’s initial findings show no major negative health impacts, Professor Krog Dahl points out the need for more investigations. She says:

It has often been claimed that the new genes in genetically modified […]