For an introduction, read this Berkeley Science Review.
And Carl Zimmer’s article in the New York Times Science section.
The human gut microbiota has been described as a “forgotten organ” that is essential to human health and happiness. Evidence suggests that commensal microbes are protective against allergy, nutrient deficiency, and certain infections. However, not all interactions between vertebrates and their microbes are friendly. Competition for nutrients and other resources can cause conflicts of interest in the metagenome, the combination of human and microbial genes. Metagenomic conflicts of interests might drive some unhealthy eating behaviors, since nutrient energy is shared between the host and microbiota. This hypothesis has implications for food cravings and the obesity epidemic.
Writing assignment (1 page max): Do you think it is likely that our food cravings are driven by the evolutionary interests of our gut microbiota? Why or why not? What are the other explanations for why we crave fatty, sugary, and salty foods? (remember that you do not need to agree with the argument in the paper.)