Personalised medicine has emerged as a novel strategy for treating disease. By combining analyses of genetic and environmental factors, treatments can be specifically tailored to the individual, thereby improving their efficacy. This approach has been particularly useful in cancer, where high heterogeneity in tumour phenotypes and microenvironments make “one-size-fits-all” treatments difficult (Block et al., 2015). The success of these personalised approaches suggests that extension to other areas, including both disease prevention and maintenance of good health, will also be fruitful. Personalised nutrition aims at maintaining and optimising health so as to prevent disease (Kaput et al., 2015b). Current nutritional guidelines are typically derived from epidemiological and associative studies and resulting large clinical databases. Therefore, they are not always useful or actionable for individuals. Indeed, a recent study demonstrated that individuals produce very different changes in blood glucose levels, even after consuming the exact same food (Zeevi et al., 2015). Therefore, in order to help individuals manage e.g. their glycaemic responses to meals, tailored solutions and recommendations must be developed. Research into personalised nutrition is accelerating, and this approach will be crucial for preventing complicated and highly individualised conditions such as metabolic disease and obesity. Diabetes research is an excellent example of how large-scale analyses have yielded insights into the disease complexity, at the level of both the population and the individual. For example, recent studies have identified numerous genetic risk factors related to Type 2 diabetes (Prasad and Groop, 2015); others are exploring the complicated relationship between genes and environmental factors (Franks and Pare, 2016), as well as epigenetic risk factors (Dayeh et al., 2016). However, understanding the enormous amount of genetic data and highly complex (and largely unknown) diet-gene interactions to design individualised nutritional recommendations poses a significant challenge. Indeed, researchers must analyse and correlate multiple kinds of data, including not just genetics, but also modifications of these genes (epigenetics), blood levels of nutrients, glucose tolerance, and numerous additional parameters. Resolving these issues will require a concerted effort from the fields of genetics and informatics, combining the latest ‘omics’ technologies with the power of big data analytics. The scope of the Keystone Symposium “Human Nutrition, Environment and Health” in Beijing, China (October 14th to 18th 2015), was to discuss both the opportunities and challenges for personalised nutrition and the application of systems biology to healthcare. The conference was organised by three leading figures in the field of nutritional and systems science, Martin Kussmann (Nestle Institute of Health Sciences, Lausanne, Switzerland), Hannelore Daniel (Technical University Munich, Germany) and Jacqueline Pontes Monteiro (University of Sao Paulo, Brazil), together with the Beijing Genomics Institute. This first-of-its-kind Keystone Symposium and unique event brought experts together from academia, public health care, and industry to discuss state-of-the-art research in the nutritional sciences. Participants from 40 different countries joined the meeting, which made for a truly global snapshot of current nutrition research. The main objective of the meeting was to explore and connect novel quantitative, comprehensive, and molecular approaches to nutrition research, with a focus on personalised nutrition. The talks of the meeting were divided into seven major topics: (1) the interaction between human genome, diet and environment; (2) translational models for human nutrition; (3) human nutritional and lifestyle interventions; (4) capturing and monitoring human individuality; (5) nutrigenomics and systems nutrition; (6) Nutrition 2.0 – translation into solution for human health; and (7) global nutrition and sustainability. The meeting brought together researchers from distinct scientific fields: nutrition, genomics, physiology, epidemiology, clinical research, analytics, and bioinformatics. These topics provided the foundation for discussions surrounding the current state of nutritional sciences. In his keynote address, Jose Ordovas from Tufts University, USA, noted that we cannot ignore the connectivity between genetics and environment for studying – and eventually understanding – how to achieve optimal nutrition. He re-introduced the concept of the ‘exposome’ (Wild, 2012). First espoused 10 years ago, it describes everything the individual is exposed to in his or her life that is not genetic. Crucial to personalised medicine is linking environmental factors to disease risk and causation, and as such may be just as significant a factor as the genome in determining phenotype; indeed, nutrition is one of the main exposomes. However, establishing causal relationships between disease and exposure is difficult, requiring interpretation of vast quantities of data.