When your blood glucose levels dip you get tired. Hence, hunger can make you tired. The opposite is also true, when you eat your energy levels rise. How quickly these levels rise and fall depends on what you have eaten. Ultimately, what causes us to feel hungry when we need to eat is the release of certain hormones, including ghrelin, says Tom Hritz, clinical nutrition manager at the Magee-Womens Hospital of the University of Pittsburgh Medical Center.
“And there are opposite hormones that signal when you’ve eaten enough and your belly is full. These hormones send the message that you can stop eating now.”
