Interesting article describing the relationship between thyroid function and obesity, and how detrimental obesity is to the thyroid and related processes. Subjects tested were children, but it's very likely this has implications for all humans.   There's a lot of good information about how the human body has defense mechanisms against and processes to stop obesity. Our bodies literally hate being fat. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3608008/