Hello, I've been wondering this for awhile. I am a 15 year old girl who has had her period for 3 years now, however, I only get it every 3 to 4 months. I also mainly get most of my calories I've realized from sugary drinks. For my meals during the day: I do not eat breakfast, I only have a cup of tea then I head to school. Then, for lunch, I rarely eat lunch, if I do, it's only a 126 calorie yogurt and a sugary drink that is worth about 140 calories a can I think.