Researchers at the Faculty of Biology at TUD Dresden University of Technology have investigated the interaction between genes and nutrition using the fruit fly as an example. Their results are surprising and show that, minimal genetic differences in the mitochondria can cause healthy food to be lethal and unhealthy food to be good. Accordingly, there is no such thing as optimal diet. The new findings could lay the foundation for personalised nutritional recommendations for humans and make a major contribution to public health.