The purpose of this research project is to investigate on the differential effects of high vs low GI diet on plasma metabolites, using an untargeted metabolomics approach, among subjects with at least two features of the metabolic syndrome. A single-blind, 12-wk randomized controlled trials was set up in 230 subjects. Plasma samples were collected at baseline(3 weeks) and post testing(12 weeks), on different time points, during a Meal Glucose Tolerance Test (MGTT). Differences in metabolic profiles between groups (Low GI/High GI) will be addressed and data analysis will be performed to see if some of the differences can be linked to dietary effects at baseline. For the analysis of the collected plasma samples, untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics will be performed. Recently, metabolomics has become an important tool for identification of metabolites that can trace specific food exposures or dietary patterns. Furthermore, metabolomics can help in the understanding of disease related metabolic processes influenced by diet (Shi et al., 2018). Plasma metabolome can help to understand cellular metabolism and it may include important biomarkers of diabetic control that can potentially correlate better with complications such as, CVD (Dutta et al., 2016). The differences between the metabolic profiles between the low GI and high GI diets will be processed with a data-treatment pipeline developed in Landsberg’s lab.