It can be normal to be hungrier on some days than others based on a number of factors such as hormones, age, gender, sleep, stress, and physical activity level. However, it is important to still eat three meals per day, plus a snack or two in order to get all of the energy and nutrients that your body needs. The portions might change slightly based on your hunger and fullness levels each day.
An eating disorder, such as bulimia or anorexia, is an illness that causes a person to purposefully starve themselves or throw up the food that they eat in an effort to be thin. If you are unsure whether or not you have an eating disorder it is a good idea to meet with your health care provider and describe your symptoms so that he or she can do an assessment. If you are worried that you might not be eating enough, you can ask to meet with a registered dietitian who can assess your meals and snacks to make sure that you’re getting enough of the vitamins and nutrients that your body needs on a daily basis.