Like most things menstruation-related, the feeling that your period may cause weight gain isn’t all in your head. In fact, there are several physiological and psychological reasons why menstruation adds pounds that may last longer than the week of your period. The good news: With some knowledge of the why and how, you don’t need to grin and bear it. Here’s what you need to know:
1. Fluid retention
Feeling bloated is a common complaint during the menstrual cycle, when elevated levels of the female reproductive hormones estrogen and progesterone lead to a shift in the body’s set point for sodium and cause fluid retention. “This may be the most noticeable to women during the second half of their menstrual cycle, when both estradiol the most potent and common of the three estrogen hormones and progesterone levels are at their highest,” says Heather Huddleston, MD, associate professor, division of reproductive endocrinology and infertility, at the UCSF Center for Reproductive Health.
To keep fluid weight at bay, avoid salty foods during the second half of your menstrual cycle. Skip the diuretics, says Amy Stephens, MD, a doctor of obstetrics and gynecology at the Cleveland Clinic. “In severe cases some women may be prescribed them, but that should be something done in conjunction with your gynecologist,” says Dr. Stephens.
2. Constipation
Your period affects how well your gastrointestinal tract works to push out waste from your body. “Progesterone causes some relaxation of smooth muscle, leading to a reduction in gastrointestinal motility, which may lead to bloating and constipation in some women,” says Dr. Huddleston. To reduce both, increase the amount of fiber in your diet, particularly in the second half of the menstrual cycle, she suggests.
3. Food intake
Progesterone plays another weighty role during the second half of the menstrual cycle. It increases appetite, causing you to eat more. “Consistent overeating that is not offset by an increase in physical activity can lead to permanent weight gain,” says Dr. Huddleston.
To keep from gaining weight, avoid foods that decrease overall well-being. “Unfortunately, you want to avoid things you really crave, like sugary foods, like lots of carbs,” says Dr. Stephens. “You want to avoid caffeine and alcohol, and really salty foods.”
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4. PMS
For most women, their monthly “cycle” starts with at least one of the host of symptoms known as premenstrual syndrome, or PMS, about one or two weeks before their actual period begins. Bloating, food cravings, and weight gain are among the most common symptoms. A study of 259 healthy women with regular menstrual cycles showed significant increases in appetite, protein intake, and total cravings, including those for chocolate, sweets, and salty flavors during the luteal, or premenstrual, phase before menstruation begins.
Experiencing depression or anxiety are also hallmarks of PMS, which is thought to be caused by cyclic changes in the brain chemical serotonin. “For some women, these mood symptoms can also lead to increased food intake,” says Dr. Huddleston. About 3 to 8 percent of women may experience a severe form of PMS known as premenstrual dysphoric disorder (PMDD), according to the American College of Obstetricians and Gynecologists. Food cravings or binge eating are one of the symptoms of PMDD. See a health professional if you experience significant depression or anxiety during PMS, says Dr. Huddleston, as they can be associated with binge eating or eating disordered behaviors. To offset the weight gain during PMS or the second half of your cycle, increase exercise and focus on consuming healthy, nutrient-rich foods.
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5. PCOS
If you experience irregular periods and weight gain, there may be cause for concern. Polycystic Ovary Syndrome, or PCOS, is an imbalance of reproductive hormones that causes metabolism problems. It affects one in 10 women of child bearing age.
In obese women with PCOS, losing weight may help regulate their menstrual cycles. “Fat itself can produce estrogen which can cause hormonal imbalances that can affect the cycle,” says Dr. Stephens. “Irregular cycles do not cause weight gain. Weight gain can cause irregular cycles.”
For most women, weight gain during menstruation is only temporary. Maintaining an overall healthy lifestyle and diet will keep those extra fluctuating pounds from becoming permanent.
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