A woman’s diet and overall weight are another probable reason for an irregular period. When consuming foods that are high in carbohydrates and gaining excess weight, the body will produce fluctuating levels of certain hormones that in turn shift when a woman ovulates. It is the same for women who lose a substantial amount of weight. Typically, for a woman to maintain a regular menstrual cycle, her body fat percentage must be at least 17-22 percent. This again has to do with the evolutionary concept that when a woman’s body is in a state of starvation, it means it is not conducive to maintaining a healthy pregnancy and growing a nurtured baby.