If your nutrient intake is out of balance, such as a low protein, you may have additional fluid moving into your tissues. Protein effects the pressure in your blood vessels and may cause a leaking of fluid from the blood into the surrounding tissue. You should not look to just your diet as a cause of premenstrual fluid retention. Hormonally, your body is retaining water the last two weeks before your menses. Your body is preparing itself for pregnancy every month.
Progesterone is the hormone that helps build up the uterine lining to support a pregnancy.
When pregnancy does not occur, progesterone decreases, the lining sloughs off and with it the additional fluid that your body retained. You will probably lose the water weight after your monthly menses is over. Also, if you limit salt intake at the table, you can lower the amount of sodium in your diet. I have been taking Lasix, a high blood pressure pill, every other day. Now my doctor has me taking one every day.