Weight gain & period bloating
In this article
What's the lowdown?
Weight gain and bloating before your period is a premenstrual symptom
It is thought to be linked to the higher levels of progesterone in the body
Eating salty foods, processed carbs and caffeine
Exercising, staying hydrated and eating more naturally diuretic foods can
Have you ever felt swollen, bloated, like you’re 4 months pregnant with a gas baby before your period?
Period bloating and weight gain during your period cycle is not all in your head. Would it surprise you that the reason why you might notice weight gain during your period or bloating during your period is because of your hormones!
Does your period cause you to gain weight?
Weight gain is reported by 90% of women along with other premenstrual symptoms like bloating, headaches and changes in mood around a week or two before your period dwhich is called the luteal phase of your menstrual cycle1. Women experience these symptoms in varying degrees and can be diagnosed with premenstrual syndrome (PMS) or premenstrual dysmorphic disorder (PMDD) if the symptoms affect your quality of life.
Weight gain before period, or PMS weight gain, is caused by the hormonal changes that happen in the luteal phase. This phase follows ovulation and finishes right before your period starts.
So you don’t actually gain fat before your period. Period weight is mainly related to water retention before your period starts. This is thought to be due to the progesterone hormone, which is the main hormonal player during the luteal phase. Progesterone triggers a hormone in the body called aldosterone which tells the kidney to retain water and sodium2. Sodium is the chemical contained in salt which makes your body absorb more water, which can make you feel bloated and swelling.
How much weight do you gain on your period?
A study found that there is an average 0.5 kg weight gain during a woman’s menstrual cycle, which is mostly attributed to fluid retention (water weight)3. Not everyone will experience weight gain. You might also notice the amount of pre-period weight you gain can change with each menstrual cycle.
Do you get fat on your period?
The weight that you may gain during your period is mainly due to changes in your hormones leading to fluid retention and more constipation. So even though the scales may change and your jeans can feel tighter during your period, this isn’t due to an increase in body fat.
Period poos
Progesterone is also responsible for the annoying constipation you might notice in the luteal phase before your period. Talk about making the bloating worse…. Progesterone causes the bowel to move more slowly, relaxing the muscles in the bowel4. The back up of poo can cause some of the bloating and weight gain you might experience.
While not everyone experiences this, I for one can confirm period poos are not fun!
How to prevent period bloating and swelling?
It is natural to have cravings before your period. Funnily, these cravings are never healthy food. Maybe a packet of doritos or a whole chocolate bar…. Comfort food to prepare us for the 7 days of cramps and bleeding. However, sadly these foods actually can worsen period bloating.
Food groups to try and stay away from during your luteal phase include:
- Salty foods
- Caffeine – not just in coffee form
- Refined sugar – natural sugars are fine
- Alcohol
- Fatty foods
Top tips to limit feeling swollen:
- Avoid salty foods (it draws more water into your blood vessels)
- Try foods that are diuretic in nature, which means they help you lose water. They include watermelon, cucumber, spinach, garlic
- Stay away from refined carbs – this leads to higher level of sugar in the blood, spiking your insulin and causing the kidneys to draw in more sodium and water which leads to more bloating
- Exercise regularly
- Drink more water – it sounds counterproductive but drinking more water can flush sodium out of your body and reduce bloating
How long does period bloating last?
Period bloating is a form of premenstrual symptom, and by definition, these symptoms will settle and improve within 4 days of starting to bleed5.
When to see a doctor about period weight gain?
Period weight gain is normal. However you should see your healthcare professional if:
- Weight gain is rapid
- Weight gain is significant
- Bloating or weight gain is only around your abdomen
- You have other symptoms such as hair loss, change to your menstrual cycle, hunger that doesn’t improve or visual changes
Dr Fatema Dawoodbhoy
Fatema is currently training in London as an Academic doctor, with a special interest in Obstetrics and Gynaecology. She is passionate about championing women to understand their bodies better and prioritise their health. She understands the importance of clinically accurate articles and has been writing engaging and educative medical content for 5 years.
Our medical review process
This article has been medically reviewed for factual and up to date information by a Lowdown doctor.
