When I’m Premenstrual I Eat Non-Stop. Why Is This?
According to research a woman’s metabolic rate increases before a period which means she burns more calories, and therefore, needs more food.
The average woman burns an extra 250-500 calories per day in the week running up to menstruation.
That said, if you are careful about the sort of food you eat, and plan accordingly by stocking up with healthy foods, then this extra demand for calories should not cause you to gain weight.