Does Birth Control Make You Gain Weight

How the pill changes your trunk shape

(Image credit:

BBC/Getty

)

Many women believe that the pill tin cause weight gain. Research hasn't plant this – but information technology has constitute that information technology tin alter body shape (and fat storage) in other surprising ways.

It'southward been blamed for polluting our rivers, destroying our marriages and – ironically – killing our sex drives. It's been called a conspiracy by the patriarchy. Information technology's even be accused of making women fancy ugly men. But for many women, i of the most off-putting charges against the contraceptive pill is that it makes us fat.

In fact, weight gain is the most commonly reported side effect of the combined pill – the most popular type, which contains both lab-made oestrogen and progesterone. This is why pharmaceutical companies listing it on the bundle.

But later several decades of research, there still isn't whatsoever conclusive evidence that the effect is real. The largest review so far examined 49 studies of the combined pill and constitute "no large effect is evident", merely also that at that place wasn't enough well-conducted research to be sure. The researchers institute this is true no affair what type of progesterone the combined pill contained (for more on the unlike kinds of pill, bank check out this article). Other studies that looked at progesterone-only pills similarly have found little evidence of an outcome.

You might as well similar these other stories in the Wellness Gap:
• The strange truth about the pill
• How the menstrual cycle changes women'due south brains
• Why isn't this type of birth control used more?

Maria Gallo, an endocrinologist at Ohio State University who co-authored the review, believes our conventionalities in the pill-weight connection is down to a natural human bias. People are experts at finding patterns all around us, even where there are none. The phenomenon, known as apophenia, is the reason nosotros may find it piece of cake to compare peppers to politicians, see the faces of Harry Potter villains staring downward at us from the clouds, or read too much into past lottery numbers. We're particularly susceptible to apophenia if we've been primed to expect a sure outcome – such as gaining weight subsequently starting a new medication.

"It's the same reason why there's this thought that vaccines tin can cause health bug," says Maria Gallo. "If you give them to a population, you're going to take some people who have health problems, whether they're linked to the vaccine or not."

Researchers haven't found evidence that the pill causes weight gain – but they have found that it can change a woman's body shape and body fat percentage (Credit: Getty/BBC)

Researchers haven't constitute evidence that the pill causes weight proceeds – only they have constitute that it tin can change a woman's body shape and body fat percentage (Credit: Getty/BBC)

In the case of the pill, Gallo points out that the average person puts on just over a pound (half a kilo) of weight each yr for near of their life, starting in early machismo – which, incidentally, is when most women start using contraception. It may exist reassuring to be able to blame this 'weight creep' on something other than overeating; terminal year she even caught women in the deed of inventing weight gain after being fitted with the contraceptive implant.

Even and then, it's non all in our heads. Though big-scale reviews haven't constitute that the pill causes weight gain, it can change a adult female'southward body shape and composition.

At that place are three big reasons for this, and they have to exercise with muscle, fluid memory, and fat.

Muscle in

Back in 2009, Steven Riechman, an practice physiologist at Texas A&M University, discovered one surprising impact of the pill, entirely by accident.

At the fourth dimension, he was researching how a person'due south genetic makeup tin affect their ability to grow their muscles through practise. His research team put a group of men and women through x weeks of resistance training – slow, punishing exercises such as crunches and lifting heavy weights. And so participants were weighed to see if they had more musculus than they started with. The squad as well gathered information on various lifestyle factors so that they could make sure whatsoever gains were acquired by genetics and not, for example, the medications they were on.

While they were doing this analysis, they discovered that women on the pill had gained 40% less musculus than those who weren't on it.

"Information technology jumped out equally a pretty big impact," says Riechman.

8 women open up about the side effects they experienced from the pill. Watch the video below.

It's well-known that men naturally accept more than musculus than women. The average man has 72lbs (33kg) of brawn, compared with a measly 46lbs (21kg) in women. This is partly just because men are taller and heavier overall, merely that isn't the whole story – every bit a pct of overall body mass, men are nearly 38% muscle while women are 31%. This comes down to hormones: men have more 'anabolic' hormones running through their veins, which tell the body when to grow more muscle.

Men tend to have a higher percentage of muscle mass than women because of their hormones (Credit: BBC/Getty)

Men tend to have a college percentage of muscle mass than women considering of their hormones (Credit: BBC/Getty)

This includes an important but little-known steroid called DHEA. It's secreted past the adrenal glands – cocktail sausage-sized organs which sit down above each kidney – and is involved in everything from keeping bones stiff to maintaining our immune systems.

The hormone used to be extremely popular with athletes, partly considering of its extraordinary musculus-building power, and partly because doping with it was legal until adequately recently. Just in case you were getting any ideas, it likewise has many drawbacks, such as the tendency to crusade liver damage and shrink a man'southward testicles.

But women produce anabolic hormones likewise – and the team institute that those on the pill had much lower levels of DHEA in their blood.

When they worked out, women on a certain type of pill had less of the muscle-building hormone DHEA – and less muscle gain – than those not on the pill (Credit: BBC/Getty)

When they worked out, women on a certain type of pill had less of the musculus-building hormone DHEA – and less muscle gain – than those not on the pill (Credit: BBC/Getty)

Fifty-fifty more than intriguingly, the poor muscle gains weren't found in all women on the pill, just those that independent a certain type of lab-made progesterone that likes to bind to the same poly peptide.

"Nosotros're pretty confident the progesterone is what's causing this," says Riechman. One possibility is that past competing for the same binding sites, the hormone may be blocking signals to grow more than musculus. The results haven't definitively proven the link, simply if it does turn out to exist real, surely women will want to know about it – particularly in the low-cal of recent fitness obsessions such as CrossFit and Instagramming your abs. "This study should absolutely be followed up. People are interested and we get calls fairly regularly most it," he says.

Fat storage

And the pill may be changing women's bodies in other means, as well. Only as it has an bear upon on the proportion of muscle in our bodies, it could be exerting subtle influences on fat – peculiarly where information technology is stored in the body.

At puberty, oestrogen and progesterone are responsible for the development of typically 'female' characteristics, such equally wider hips and larger breasts, largely by irresolute the way fat is distributed. The hormones are too frequently given to transsexuals for the same reason.

The womanly 'hourglass figure' emerges as different kinds of fat tissue respond differently to these reproductive hormones. For instance, subcutaneous fat – the kind of chub that women acquit around their thighs, hips and breasts – contains lots of oestrogen receptors.

Because hormones react differently with each type of fat tissue, changing a woman's hormone balance could alter where her fat is stored (Credit: BBC/Getty)

Because hormones react differently with each blazon of fat tissue, changing a adult female'south hormone balance could alter where her fat is stored (Credit: BBC/Getty)

Information technology'southward piece of cake to come across how, theoretically, changing a adult female'south hormone remainder could modify where her fat is stored. Some research has borne this out: ane early study found that women on pills with higher levels of oestrogen tended to take pear-shaped bodies and more than subcutaneous fatty, though non necessarily more than fat overall.

Cell swell

Finally, there's the top menace of many women on the pill: bloating.

That icky, swollen feeling happens because oestrogen also affects the fashion the trunk metabolises h2o, by influencing the production of certain proteins in the kidneys. The cease result is that the trunk retains more than fluid than it ordinarily would. This then seeps into fat cells, causing them to swell upwardly. Because women tend to store more fat in their breasts, hips and thighs, these areas tin expand the most.

Oestrogen can cause the body to retain more fluid, including the type used in the contraceptive pill (Credit: BBC/Getty)

Oestrogen tin can cause the trunk to retain more than fluid, including the type used in the contraceptive pill (Credit: BBC/Getty)

This too happens on a smaller scale in women who aren't on the pill, during the calendar week but before their period. But it's exaggerated by the contraceptive because constructed oestrogen is six to 10 times more potent than the natural kind, and considering it'southward taken nearly every solar day, which ways the levels of both hormones are more abiding.

So while the pill may not be leading to long-term weight gain, some women could still find that their dress fit differently.

Fluid retention may too help to explain why some women written report that the pill increases their cup size. In that location accept been very few studies into the effect – understandably, near enquiry tends to focus on breast cancer rather than size – but back in the 1990s a couple of Swedish scientists decided to take a look.

The contraceptive pill is known to increase a woman'southward risk of developing breast cancer slightly, both while she'southward taking information technology and in the 10 years subsequently. The researchers wanted to know whether this might be because these women have larger breasts; there's an inherent hazard in having (or growing) more cells, which is one reason alpine people tend to exist more than susceptible to cancer.

To find out, the team tracked the monthly cycles of 65 healthy women who either were on the pill, used to take it, or had never taken information technology. They plant that not but did pill users have significantly larger breasts overall, but they were especially large at certain times of the calendar month. Women who had previously been on the pill had an average-sized bust.

One study found that the pill appears to increase breast size, and not just from water retention (Credit: BBC/Getty)

One written report found that the pill appears to increment breast size, and not only from water retentivity (Credit: BBC/Getty)

The team didn't check the women'due south chest measurements before they started taking the pill, so it could exist argued that these women had always had larger breasts. However, it seems likely this was due to the contraceptive pill, considering their breast sizes weren't linked to the normal factors you'd expect – such as their pinnacle, BMI, or body weight – as in the women who weren't on the pill.

Exactly how this happens remains a mystery. The breast expansion could just be swelling from fluid retention, but another possibility is that the hormones in the pill are really causing women'south breasts to grow. For example, the burst of growth that happens each month, and is necessary to maintain a constant size, could be lasting a bit longer. This would atomic number 82 to more tissue overall – and explain the heightened cancer risk.

Of course, whatever subtle furnishings the pill has on your figure – for improve or for worse – millions of women experience that it'due south worth it. As one Reddit user put information technology, no nascency control at all is likely to atomic number 82 to 25 to 35 pounds (11-15kg) of weight proceeds over the grade of 9 months.

This story is part of the Health Gap, a special series about how men and women experience the medical system – and their ain health – in starkly different means.

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