Eating in moderation during menstruation is generally not fattening, but sustained overeating may also lead to weight gain and needs to be analyzed on a case-by-case basis. Menstruation is the result of fluctuating estrogen and progesterone levels causing the endometrium to lose its nutrient supply and then peel off and bleed, and it occurs once a month in women of normal fertility. Hormonal changes in the body of women during menstruation and accelerated metabolism lead to the consumption of more energy, so eating in moderation will not gain weight. Diet during menstruation should be light and nutritious, you can eat some iron supplement food such as red meat, pork liver and other food, avoid eating cold and stimulating food. Care should also be taken to avoid overeating, as consuming too many calories may also lead to weight gain during menstruation. Low resistance during menstruation, if you have any discomfort, you should go to the hospital in time.