Bikini Season Is Coming: How Does Your Beach Body Affect Your Hormones?

With summer around the corner, most of us have at least a few bikinis added to cart. While some swimsuit ads have gone fully “body positive,” influencers, celebrities, and the rest of social media often still promote the same svelte physique that has always been considered a bikini body. The rise of drugs like Ozempic makes staying extra thin even easier for celebs willing to dish out the cash, and it’s not uncommon for fitness influencers to claim that for the small investment of 500 sit-ups a day, you too can have rock-hard abs. Meanwhile, the “healthy at any size” movement claims there’s nothing wrong with obesity and the only downside to extreme physiques is fatphobia. So, is fat just an accessory to put on and take off seasonally? And why do we even have it anyway?

Why We Need Fat

Fat is misunderstood. Most people learn about the organs of the body and picture the usual systems: digestive, cardiovascular, and maybe reproductive, if you’re in high school health class. But our typical mental models of the body don’t include fat, probably because it seems like just excess tissue floating around in the body. In many cases, we’re only taught about how fat stores energy, and you wouldn’t be crazy for assuming it works like a camel’s hump, emptying and filling based on our energy intake. But fat isn’t passive, and energy storage isn’t the full story. It’s actually an organ with some important functions.

Fat both produces hormones and uses them to communicate with other parts of your body.

Beyond just storing energy, fat both produces hormones and uses them to communicate with other parts of your body. This can affect the hunger and fullness signals you feel, as well as affect your immune responses, since adipose tissue, or fat, has its own active immune cells. It’s also an important producer of estrogen, especially for post-menopausal women. These functions mean that having extremely low body fat, like the levels needed to have abs as a woman, can be really unhealthy. 

Abs-olutely Unnecessary

Men's and women’s bodies function very differently. Your “essential body fat,” or the body fat percentage required for your body to function normally, is very different than that of a man's. Men’s essential body fat is around 3%, while women’s sit closer to 12%. Since fat is one of the main sites of estrogen production, having a body fat percentage low enough to show visible abs (for most women) requires maintaining a body fat percentage that would cause the body to stop ovulation, causing amenorrhea, thyroid problems, and a host of other issues. 

It’s important to note that the 3% and 12% figures are the bare minimum for survival, thus “essential.” They’re an absolute minimum, not recommended body fat percentages. For context, visible abs tend to start around 15% and lower for men and about 20% and lower for women. (Note: These are body fat percentages, not to be confused with body mass index, or BMI, percentages.) However, we all carry body fat differently, so there are some women whose abs show at a higher body fat. If you’re naturally lean in the tummy, having visible abs isn’t necessarily a reason to panic. Still, don’t let male-centered fitness advice cause you to view abs as the ultimate marker of health.

The Hormone Horseshoe

Hormonal issues start to happen at both high and low body fat percentages. The “healthy at any size” movement likes to talk about how people can be obese but have no health issues. The problem is, obesity itself is a health complication. Specifically, obesity refers to when “the body runs out of tissue to store lipids in, so the existing fat cells have to grow,” meaning obesity is a disease of chronic, low-grade inflammation. This, in turn, affects how a woman’s body stores sex hormones, as well as the part of the brain that regulates ovarian function. This plays a huge role in reproductive disorder and increasing the likelihood that women won’t ovulate. Obese women are three times more likely to be unable to conceive because they aren’t ovulating. Obesity is also associated with menstrual disorders, miscarriage, and adverse pregnancy outcomes. It can also contribute to PCOS, one of the leading causes of female infertility.

Trying to look healthy at the expense of actually being healthy simply isn’t worth it.

The catch? Many of the same issues apply to women who are underweight or have the kind of extremely low body fat needed to maintain visible abs. Although being underweight is a far less common issue in the U.S. (it affects only about 1.6% of American adults, compared to 40% who are obese), it’s something to be cautious of if you’re trying for both babies and a ripped bikini body. Being underweight can also prevent you from ovulating; women who are underweight are more likely to take more than a year to get pregnant, and they are 72% more likely to miscarry in the first trimester. Abs might be pushed on women by the fitness industry, but trying to look healthy at the expense of actually being healthy simply isn’t worth it.

Closing Thoughts

Bodies shouldn’t go in and out of style, and no amount of snatched bikini pics is worth destroying your hormonal health. Whether you’re trying to conceive or just trying to regulate your cycle, keeping a healthy weight is key. Running to the extremes, whether obesity or the ever-elusive quest for abs, isn’t a healthy way to treat your mind or body. Fat is a crucial organ, not a seasonal accessory.

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