With the increasing obesity epidemic, obesity co-morbidities are major health problems worldwide. It is crucial to identify U.S.-grown crops that can combat obesity-associated disorders. As edible brown seaweeds exert various health-promoting effects, seaweed farming for human consumption has been expanding in the U.S. However, studies on health benefits and safety of U.S.-grown seaweed is limited. The primary goal of this proposal is to evaluate whether consumption of U.S.-grown sugar kelp can counteract high fat-induced metabolic and inflammatory stresses with elucidating mechanisms, focusing on the contribution of the gut microbiota to the health benefits of sugar kelp. To achieve the goal, we will determine the role of the gut microbiota in the antagonistic effect of sugar kelp on obesity and its associated metabolic dysfunctions and inflammation in the liver and white adipose tissue (WAT) of diet-induced obesity mice. Particularly, we will assess the roles of sugar kelp in modulating energy expenditure via WAT browning and changing fecal energy excretion. Furthermore, we will evaluate iodine and heavy metal toxicity in vivo. Therefore, results from this study will be directly applicable to U.S. agriculture and will provide scientific evidence on the health benefits and safety of U.S.-grown sugar kelp to establish dietary recommendation of sugar kelp for the prevention of obesity-associated metabolic and inflammatory diseases. This study reflects the priority of the Food and Human Health Program priority, "Investigate the role of the food components or contaminants on the human gut microbiome and its metabolites, and the subsequent impact on human health."