Many women experience weight gain during the premenstrual phase or the two weeks immediately before their periods. Some of this weight gain is temporary and is caused by fluid retention in the body resulting from hormonal changes. Sometimes, certain food cravings during the premenstrual phase may result in binge-eating that eventually causes weight gain. If a woman has bad period pain, headaches, or mood changes, she may be less likely to adhere to her regular exercise routine. Limited exercise, combined with increased eating, work together to increase weight. Certain antidepressant medications may also cause weight gain as a side effect.

There are several ways to reduce weight gain during the premenstrual phase. A regular exercise routine and a balanced, nutritious diet are the most important lifestyle factors. Foods high in refined sugars should be replaced with those that are high in complex carbohydrates, protein, and fiber. Food cravings can be managed by getting adequate sleep, eating smaller and more frequent meals, limiting caffeine intake, staying well hydrated, and doing at least some exercise. Reducing salt intake in the last few days before ones period can help minimize bloating and fluid retention. If fluid retention and bloating are pronounced, a diuretic such as spironolactone can be used to remove excess fluid from the body. Calcium supplements may also help reduce bloating and other PMS symptoms.

If a woman is on antidepressant medication, she can discuss with her physician the possibility of switching to a drug that does not cause weight gain. If this is not possible, weight loss strategies, such as increased exercise and a diet that restricts the total number of calories consumed, can help. Discontinuing antidepressant medication may result in worsening depression and should not be considered as a weight loss option.