11.Migraine
A pounding head alone can be enough to make you lose your appetite. But a migraine also can cause nausea and vomiting. And you may not feel like eating even after it goes away. A dip in hunger is common in the day or two after a migraine. Medications can help prevent them or treat them when you have them.
12.Depression
For some people, this can lead to cravings and weight gain. For others, it can have the opposite effect. Depression triggers your brain to release more of a hormone called corticotropin-releasing factor (CRF). It can make you less hungry. With severe depression, you may lose interest in cooking and eating. If your change in appetite comes with a change in mood, talk with your doctor about it.