Weight gain during your period: Why it happens & tips to avoid bloating

Before we dive in… This article talks about weight and how the body changes during the menstrual cycle. We always aim to unpack the science behind the topics we cover and approach them with care, but we know that this topic can be a difficult one for some people. If you have specific questions or concerns about weight, we always recommend discussing this with your doctor first.

Do you gain weight during your period?

It’s possible! Research suggests we can actually gain a bit of weight during our periods. 

While there haven’t been a ton of studies done about this topic, some have found that body weight can change during the menstrual cycle and that women tend to gain a little weight during the luteal phase and menstruation [1, 2, 3]. Although these studies have been quite small, they support what many of us experience during our cycles. However, it’s also worth noting that there have been other studies that found no link between the menstrual cycle and weight gain [4].

It’s possible that some people experience weight gain and others don’t, but there are also other explanations for why we might feel like we gain weight on our period. One such example is bloating. This is a very common PMS symptom in the days leading up to and during our period [5], and while bloating isn’t the same as weight gain, it can both cause discomfort and make our belly swollen, so our clothes fit a little tighter — giving the perception of weight gain.

How much weight gain is normal during your period?

There hasn’t been enough research done on this topic to give an exact range of how much weight it is normal to gain during your period (or even to say for certain that it happens to everyone), but it’s most likely not a huge amount. 

For example, one study that followed 42 women during their cycle found that, on average, body weight increased by 0.5 kg (about 1 lb) during menstruation. This was explained by the fact that we tend to hold on to more water during menstruation (more on that soon) [1]. Another study that included 40 athletes found similar weight changes of between 0.5 and 0.8 kg (roughly 1–1,8 pounds) [3].

Of course, everyone’s body is different, and these studies only included a very small number of women, so it’s possible you may notice smaller or larger changes to your weight than what was described there (or no change at all). It may even vary from one cycle to the next.

It’s also important to keep in mind that our weight isn’t necessarily a fixed number. Aside from changing with the menstrual cycle, our weight will naturally fluctuate a bit day-to-day depending on many different factors, for example, if you’ve recently eaten, had something to drink, or even whether or not you’ve gone to the bathroom yet. More permanent weight changes take a bit longer to happen, so you won’t suddenly gain or lose a couple of pounds of fat (or muscle, for that matter) overnight.

Why do I gain weight during my period? 

So, what could cause us to gain weight during our period? Studies that have looked at body composition (how much of our body mass consists of muscle, fat, bone, and water [6]) during the menstrual cycle have found that body fat doesn’t tend to fluctuate in the different phases of the cycle [7]. This means that period-related changes to our weight are likely the result of something else — and the main culprit seems to be fluid retention. 

Fluid retention around our periods is sometimes referred to as “menstrual edema” in scientific literature [5]. Essentially, it means that the body is holding on to more water than usual. This extra fluid can make us a little more swollen, and you might notice it in different parts of your body, for example, around the belly, breasts, or even in your face or legs [8].

One study, which followed women for a year to study fluid retention during the menstrual cycle, found that not everyone experienced it. However, for those that did, fluid retention usually started building up in the days before menstruation and then peaked on the first period day, after which it started decreasing again [5]. 

Do hormones cause weight changes during the menstrual cycle?

Long story short: it’s possible, but we don’t know enough about it yet. The menstrual cycle is mainly governed by our two main sex hormones: estrogen and progesterone. Estrogen levels increase during the follicular phase (from the first period day until ovulation), and peak on ovulation day. After ovulation, estrogen levels drop and progesterone increases instead (this is what causes the temperature rise after ovulation). When our period starts, progesterone levels drop again — and both hormones are low during our periods [9]. 

Research has shown that estrogen and progesterone help regulate fluid retention in the body. Very simplified, both high estrogen and progesterone levels can lead to more fluid retention, and these hormones also seem to interact with each other [10].

Since weight gain during our periods appears to happen because the body is retaining extra water [1], it seems plausible that our sex hormones would play a role when it comes to weight changes during the menstrual cycle. However, it doesn’t appear to be so clear-cut. In the study that specifically looked at fluid retention during the menstrual cycle, there was no correlation between estrogen and progesterone levels and fluid retention. In fact, fluid retention peaks when the levels of both of these hormones are at their lowest — during menstruation [5]. So all in all, more research is needed to understand what's going on.

What is period bloating?

Bloating is another thing that can affect how our body feels and looks during our period. It’s characterized by a feeling of fullness or discomfort in the belly, and it can also make the stomach swollen [11]. 

There are two main causes of bloating: excess gas buildup in your stomach and (again) fluid retention [11]. Research has found that as many as 65% of those who experience PMS symptoms also retain more fluid during their period [8], so period bloating and fluid retention do seem to go together.

Bloating can happen at other times in the menstrual cycle as well. For example, some of us may experience bloating during ovulation or as a luteal phase symptom in the lead-up to our period. 

Tips to avoid period bloating

At this point, you might be wondering if there’s anything you can do to avoid or alleviate bloating and fluid retention on your period — and yes, there are some things you can try!

• Drink plenty of water: We know it might sound strange to drink more if you’re retaining water, but it can actually help the body get rid of excess water and reduce bloating [11].

• Limit your salt intake: Salt can make the body retain more water, which may lead to worse bloating [12]. Though we know many crave salty foods during this time, it can be worth trying to limit your salt intake if you tend to feel bloated during your period or when you have symptoms of PMS.

• Eat less sugar: Again, we know period cravings aren’t on our side here, but sugar can also leave us feeling more bloated [11]. Finding a good balance between managing symptoms and enjoying some treats here and there is the key — make sure you listen to your body.

• Cut down on caffeine: Caffeine can irritate our stomach and make bloating worse for some people, so cutting down on coffee or tea can help [11]. 

• Eat plenty of fiber: Fiber is great for getting the stomach to move smoothly and can also help reduce bloating (plus it’s great for our health in general) [11]. Fruit, vegetables, legumes, whole grains, seeds, and nuts are all rich in fiber, so you can incorporate them into your diet.

• Eat smaller meals: Big meals can be hard on the stomach, so opting for smaller meals more frequently can help with digestion and reduce bloating [11].

• Movement: Gentle exercise can help reduce bloating [13]. Try to find ways to move during the day that work for you to help with symptoms and make you more comfortable. For example, check out our guide on yoga for period cramps. 

• Magnesium: Research has shown that magnesium can help with PMS symptoms, and specifically with fluid retention [14] and period cramps [15], so you can try magnesium supplements to help alleviate symptoms. However, it’s also worth noting that a possible side effect of magnesium is digestive issues, so it’s always a good idea to check with your healthcare provider before starting supplements to see if it would be a good option for you.

And as always, remember that we’re all different, so not all of these tips will work for everyone. If you tend to feel bloated around your period, give them a try and find what works best for your body.

Period cravings – what are they and why do they happen?

Do you find you crave chocolate or other foods during your period or in the days right before? Then you’re not alone — it’s actually a common PMS symptom. Research has found that it’s especially common to crave salty or sweet food during the late luteal phase [16]. 

How hormones affect our appetite

It’s no secret that our hormones have a big impact on how we feel, and our appetite is no different. Many of us report feeling hungrier at certain points in our cycle, and this is linked to natural hormonal fluctuations.

Estrogen, the dominant hormone in the follicular phase, has been linked to lower appetite, which can explain why we may not feel as hungry during this first phase of the cycle. On the other hand, higher progesterone levels in the luteal phase can increase our appetite [17], and studies have shown that we tend to eat more during the luteal phase [18].

Other causes of period cravings

But we can’t blame it all on estrogen and progesterone — period cravings can also have other causes. For example:

• Stress hormones in flux: When our period starts, there is also a shift in hormones that regulate our bodies’ stress levels. Serotonin, a hormone that makes us feel calm, decreases at this point in our cycle, which can make us crave comfort food as a way of boosting serotonin levels [19].
• Dehydration: If we’re dehydrated, this can make us feel hungry even though we’re actually thirsty — another reason why it’s important to drink enough water during our period (aside from helping with fluid retention).
• Learned cravings: There is actually some evidence that suggests that period cravings, especially for chocolate, may be a cultural phenomenon. A small study that compared US women with women who were born in other countries and later moved to the US found that US women were more likely to crave chocolate during their periods, while the other group had chocolate cravings that were less linked to specific times in their cycle. This suggests that, at least partly, cravings may be something we learn as we grow up in a culture [20].

Tips for managing feelings around period weight gain

Many of us may feel pressure around our bodies, and even though we know our worth isn’t tied to our weight, seeing the numbers on the scale go up or feeling our clothes fit a little tighter around our period can be challenging. Here, we’ve listed some tips to help you feel more comfortable during this time:

• Wear comfortable clothes: Choose clothing that feels comfortable on your body. If you’re bloated and your tummy is swollen, it can feel worse if your clothes feel constricting. Pants with a soft lining, a dress, or similar clothing can make you feel more comfortable.

• Try mindful eating: We know it’s easy to rush through meals, but try to slow down and be in the moment. Mindful eating is about focusing on the taste and texture of the food, as well as how it feels in your body, and paying attention to your body’s hunger signals without judgment. Still hungry and enjoying the food? Have some more. Are you feeling full? Then you don’t have to eat more. Eating more slowly and paying attention to it can not only help with digestion (which helps with bloat), but it can also make the meal more enjoyable and help lessen negative feelings around food [21].

• Don’t restrict yourself: Whether it’s chocolate, salty snacks, or some other treat, know that it’s okay to eat what you crave. Many of us have a somewhat complicated relationship with food, and it’s common to feel guilt when indulging in cravings. However, we shouldn’t have to feel guilty about eating something we like. To keep our bodies nourished, we need a healthy balance of carbs, fats, and protein in our diet, but it’s important to make room for foods we enjoy, too.

• Be kind to yourself: We know it may be easier said than done, but try to be kind to yourself and your body. There’s a lot of pressure from society around weight and how our bodies look, but try to appreciate your body where you are. Focus on activities you enjoy without needing to achieve anything in particular. Selecting what content we consume, for example, on social media, can also help tune out outside pressure.

Understanding what happens in your body and why your weight can fluctuate during the menstrual cycle can be helpful in itself. By knowing what to expect, you can feel prepared ahead of time, and that may make it easier to be kind to yourself and your body during these natural shifts. However, if you struggle with food and eating, reach out to your healthcare provider. You don’t have to go through it alone. 

Manage bloating and understand your menstrual cycle with NC°

Here at Natural Cycles, our goal is always to empower you with the knowledge you need to take charge of your own health. The NC° app allows you to keep track of symptoms during your menstrual cycle, including bloating, and helps you spot trends over time. You’ll also get notified when your period is approaching and when you might start noticing PMS symptoms, so you can feel prepared and in control of what’s happening in your body. 

Natural Cycles is more than just a birth control method — it’s a trusted fertility partner that grows with you, with five app modes designed to support you whether you want to prevent, plan, or follow a pregnancy, recover after giving birth, or understand your body’s changes during perimenopause. Why not see if Natural Cycles could be right for you?