Recent sleep quality can significantly affect blood test results for metabolic markers.

“So that finding, which was fairly serendipitous, stimulated a whole line of research. After that, the next area of exploration was looking at all sorts of metabolic hormones, hormones that are involved in the regulation of energy expenditure or hunger. And these are things like leptin, which is released from fat tissue, and is a signal to the brain of how much fat we're storing on our body. Also, another hormone called ghrelin, which is released by oxyntic cells in the stomach. And that's a fascinating hormone, because it does quite a lot of things, but it's the only gut-derived hormone that will actually stimulate hunger.”