How much weight do you gain on your period? The causes of period weight gain

Sadly, it's not a myth
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  • Gain weight on your period? You’re not the only one. From bloating, mood swings to annoying skin breakouts, life’s not always much fun at certain times of the month. But knowing what to expect, (and when) can often help.

    That’s why we asked our expert, Alison Cullen, Nutrition Practitioner and Health Education Manager for A.Vogel, the real reasons you gain weight on your period and what you can do to help it.

    Why do you gain weight on your period?

    “There are a variety of factors involved,” says Alison. And this depends on where you are in your cycle. Alison says:

    After you’ve ovulated: “Firstly, as levels of the sex hormone progesterone rise, they influence the amount of a fluid-regulating hormone called aldosterone. If your diet is quite high in salt, this can tip you over into retaining fluid. Leaving you bloated and tired.”

    Last week of your cycle (before you bleed): “Next, as levels of the mineral chromium fall, you may experience sugar or carb cravings. A sudden influx of refined carbs will add bloat and show up when you weigh in. You are also more likely to experience constipation. A couple of days of reduced bowel movement will have a surprising amount of effect on the scales.”

    Just before your bleed: “You may feel extra-tired, as levels of the sex hormone oestrogen fall. Inspiring yourself to rush out and exercise may be tricky at this point, and less exercise may mean more poundage (especially if you are consoling yourself with a packet of comforting biscuits).”

    Start of your bleed: “You may feel a little more bloated or distended as your womb is now engorged with blood. This is in anticipation of the implantation of a fertilised egg, which is great if you want to get pregnant, but not if you’re working on maintaining a streamlined silhouette. The good news is, this isn’t weight gain and it isn’t permanent – things are about to shift.”

    During your bleed: “You are losing iron. If you are already deficient or even borderline in this important mineral, fatigue will now claim you for its own. You’ll also feel dizzy, chilly, and light-headed. Supplementing with a natural iron tonic is very sensible if this is you.”

    The real reasons you gain weight on your period: hitting the biscuit jar is tempting at this time

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    How much weight do you gain on your period?

    “This entirely depends on the factors above, and how many of them pertain to you,” says Alison. “Some women barely notice their period, with just a little bloating during their bleed. Others may find their weight bobbing around by as much as 3-5lb/1-2kg.”

    When does period weight gain start?

    “Although you may feel more bloated and uncomfortable during your bleed, weight is more likely to show on the scales in the run-up,” says Alison. “The factors influencing weight gain on your period begin to show their effects in the second half of the cycle. This is technically referred to as the luteal phase. This is usually the 3rd and 4th week after you start your bleed, after you ovulate (around 2 weeks after you start your bleed).”

    When does period weight go away?

    “As the effects of your bleed die away and your womb is at its smallest (having shed its lining), your weight will reset to normal,” says Alison. “This should last through the next couple of weeks, assuming your lifestyle isn’t driving weight gain.”

    Is it harder to lose weight on your period?

    “Yes. The best way to counter weight gain on your period is to work on various different factors,” says Alison. She suggests:

    • Drink plenty of still, plain water. “This will ensure you don’t retain fluid. The less water you drink, the more the body thinks there’s a drought and starts hanging onto every bit of water it can. Drinking plenty will keep things moving smoothly.”
    • Avoid salty foods. “You don’t want a heap of sodium (from salt) in your system, as that just encourages fluid retention.”
    • Try a supplement. “If you become a carb monster as your bleed approaches, take a chromium supplement and try a month or two of Molkosan Fruit (£7.50, It’s a prebiotic which supports better digestion.”
    • Eat lots of veg. “Even when you feel more like cake! The fibre in veg is very helpful for the gut. Try nibbling on dried fruit instead of (or at least in between) the biscuits, to provide more helpful fibre and mineral-drenched sweetness.”
    • Stay active. “Even if you can’t muster the energy for your usual exercise regime, stretch and do some gentle walking. It will keep your circulation brisk and your muscles from cramping.”
    • Pick a herbal healer. “Agnus Casus (£10.50, is a licensed herbal remedy that helps to relieve symptoms of pre menstrual syndrome. But it should not be taken by anyone using hormonal contraception, including the pill, implants or coil. This is because the remedy works to raise levels of progesterone, which can work against the action of the contraceptive.”

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