One of the significant causes for changes in the menstrual cycle or reasons for having irregular periods is an eating disorder.
A poor or nutritionally inadequate diet, which is characteristic of a person with eating disorders, will negatively impact many bodily systems and the menstrual cycle can well go haywire because of this. This is because eating disorders impact the production of hormones and therefore affect a woman’s cycle.
Another characteristic of someone with an eating disorder is extreme exercising which may also impact and alter the menstrual cycle. Excessive weight loss can have the effect of altering the menstrual cycles.
Eating disorders can cause a condition called hypothalamic amenorrhea which is associated with low body weight (defined as weighing 10 percent below ideal body weight), small percentage of body fat, very low calorie or fat intake, emotional stress, strenuous exercise, as well as some other medical conditions or illnesses.
If the root cause, i.e. the eating disorder is addressed and after making certain lifestyle changes, such as eating a higher calorie diet, gaining weight, reducing the intensity or frequency of exercise, and reducing emotional stress, the irregularity will often reverse itself.