Why am I gaining weight near the beginning of my menstrual cycle?

By Jessah Robinson, Adv Dip (Nut Med)

For many women out there, you may be relieved to discover that during the lead up to day one of your menstrual cycle, it’s normal to gain 1 to 3 kg of weight. Thankfully, this tends to go away after a few days of starting your period. This is one of the many unfortunate symptoms of PMS (Premenstrual syndrome).

So, what causes it? Here are some reasons you may be feeling a little pudgier around this time:

Hormonal changes

Hormonal changes can cause weight gain by increasing water retention. In the few days leading up to your period, the hormones oestrogen and progesterone rapidly decline. This prepares your body for menstruation but can also cause water retention and the associated swelling or puffiness in your breasts, stomach or extremities. Believe it or not, staying adequately hydrated is a great way to prevent your body from retaining water and will help ease any abdominal discomfort.


Bloating or stomach cramps can make you feel slightly puffier than usual, especially around the abdominal area. During the early stages of your period, hormonal changes can increase gas and water retention, even causing your stomach to physically protrude. Bloating can start up to 5 days before your period and go on for the first few days of menstruation. This is similar to stomach cramps which tend to begin a couple of days before your period and can last for up to three days. Magnesium may help to reduce muscle cramps.

Food cravings

The week before menstruation, progesterone increases; this acts as an appetite stimulant. At the same time, oestrogen levels drop. Oestrogen regulates serotonin, the neurotransmitter that plays a role in your mood and suppresses appetite. As a result of the decline in oestrogen your body will start to crave sugar or high-carb foods to help the body make serotonin. This of course can lead to increased calorie intake and consequent weight gain.

GI Issues

The increased progesterone that occurs the week before your period reduces muscle contractions, this results in slow digestion and constipation. This of course leads to discomfort and bloating in your stomach and can make you feel like you’ve put on weight. You may benefit from taking Ultimate Gut Health, which promotes healthy gut bacteria, soothes the gut lining and is great for relieving gas, bloating, constipation and diarrhoea.

Lack of movement

During the lead up to your period you are also likely to experience fatigue and low energy due to lowered estrogen levels and raised progesterone levels. Because of this, it may feel uncomfortable to exercise and you will feel less motivated. During this time, rather than do anything high impact like HIIT training or CrossFit, you would benefit from doing low impact exercises like Yoga, walking or cycling. Exercise is excellent for increasing circulation which reduces bloating and water retention.

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