Goodson and colleagues29 hypothesized that the oral microbiota could (a) affect the gastrointestinal tract to increase metabolic efficiency, resulting in increased fat storage; (b) affect leptin or ghrelin levels, resulting in increased appetite and food consumption; and/or (c) affect TNF-α and adiponectin pathways, resulting in insulin resistance and increased fat storage. Here, TNF is linked to Insulin resistance.