Obesity is known to have effects on cellular metabolism, which is reflected in a person’s circulating metabolome. Metabolomics, defined as the measurement and study of circulating small molecules that are the substrates and products of cellular metabolism, is increasingly used by epidemiologists to provide a functional read-out of bulk cellular activity and a proxy to individual current health. This approach also provides insight into biological pathways linking exposures and disease.

Measuring the metabolome of people with measured body mass index (BMI) allows us to look for ways in which BMI affects the metabolome. Metabolites found to be associated with BMI can then be further investigated and linked to cellular pathways – knowledge which will help us to understand the pathology of obesity. We have already begun to look at how bariatric surgery (within the By-Band-Sleeve trial (BBS), https://bristoltrialscentre.blogs.bristol.ac.uk/details-of-studies/by-ba...) and non-surgical weight loss interventions (within the DiRECT trial, https://www.directclinicaltrial.org.uk/) affect the metabolome, and we want to use the recall-by-genotype (RbG) Metabolon data in ALSPAC (https://onlinelibrary.wiley.com/doi/full/10.1002/oby.23441) to compare our results to population-level data. Bringing together data from these different study designs enables to unpick the metabolomic effects that are associated with BMI and their relevance to disease.