Williams has a strong interest in the field of microbiota and its impact on human health. While completing a PhD in biotechnology and microbiology in France, he examined the probiotic and nutritional potential of lactic acid bacteria present in the microbiota of a fermented cereal based food using a molecular approach. At the University of Toronto and Samuel Lunenfeld Research Institute, he is currently investigating the effect of environmental factors and genotypes on human microbiome composition in the context of the prospective cohort Genetic, Environmental Microbial (GEM) project. His projects involve multiple skills and knowledge of various scientific fields, including advanced biostatistics, human physiology, human genetics, human microbiome, and human nutrition. His main project focuses on the effect of human genetics on microbiome composition and function.