A common perception is that women gain weight during their menstrual cycle. However, that is not always the case. The most common cause of weight gain is water retention. But other menstruation-related issues such as PMS and an increased metabolism can contribute to weight loss. Period-related weight changes are usually temporary.
Several factors can affect your appetite during your menstrual cycle, causing you to lose weight. Abdominal cramping can occur before and during your period. The achiness and pain can be debilitating for some women, causing them to miss work or other everyday activities. While over-the-counter painkillers can provide relief, they also can upset your stomach, having an additional effect on your eating habits.
An underlying factor in weight loss during your menstrual cycle is that weight fluctuates at different points during your cycle. You might retain water before your period starts and then lose it later. You might experiences changes in appetite in response to hormonal fluctuations. All of these changes can affect your weight.
Premenstrual syndrome includes a host of symptoms that can affect your weight, according to the website KidsHealth. Symptoms include gastrointestinal distress. You might have food cravings, but you also might have other symptoms such as irritability and headaches that can cause you to miss meals.
Your metabolism fluctuates during your menstrual cycle, which can have an effect on your weight, especially if you are dieting. A 1989 study in the "British Journal of Nutrition" found that metabolism can increase up to 10 percent in the days before menstruation begins. This increase can result in some weight loss, especially if you are experiencing other symptoms that affect your eating patterns.
Some women experience especially heavy menstrual flow. The Office on Women's Health recommends that you consult your doctor if your period lasts more than seven days or you are changing your tampon or sanitary pad every two hours or less. Also be alert for symptoms of toxic shock syndrome, a bacterial disease that can cause symptoms such as vomiting and diarrhea. If you experience any of these symptoms, see your doctor; in some cases, this disease can be fatal.