Giving entire food groups the boot is an undeniable diet trend right now. It seems like everyone knows someone (or knows someone who knows someone) who’s on a restricted or elimination diet. Keto? Yep. Paleo? Naturally. January Whole30? Been there, done that.

The more I heard about these eating styles (and their lauded benefits), the more I started to wonder if my own eating habits needed investigating. How was my diet impacting my body’s everyday function?

As my curiosity grew, I decided to give the popular Whole30 elimination diet a go. The protocol requires you to cut out all dairy, grains, legumes, alcohol, and sugar in favor of whole foods. (Whoa, right?)

As a vegetarian, I found myself feeling pretty restricted on the program. A big chunk of my pre-Whole30 diet leaned on soy products (like tempeh and tofu), legumes (like beans and lentils), and dairy. In my first week, I felt pretty low-energy. I struggled to get through my usual workouts, felt like my mood could swing at any moment, and lacked drive to spend time with friends. Then, I got my period—way early. The sudden shift out of my clockwork-like cycle freaked me out. Had restricting the types of foods in my diet impacted my hormones so quickly? I had to find out.

Turns out, your diet can have a pretty heavy impact on your hormones. In fact, after digging in, I learned my mood swings and early cycle were a pretty common side effect of restrictive diets.

The Hormone-Diet Connection

According to John Hopkins Medicine, three major glands regulate your hormones: the hypothalamus, pituitary, and adrenal glands. Together, these three glands regulate your energy, mood and emotions, sex drive, response to injury, stress, metabolism, and more. Outside factors, including diet, exercise, and stress, can impact how these glands function.

Because women’s health depends on more hormones than men’s, women are more susceptible to experiencing hormonal issues after making drastic dietary changes, says Adeeti Gupta, MD, FACOG Gynecology and Women’s health Presidential Leadership Scholar, Fonder, CEO Walk In Gyn Care. The specific changes vary based on the individual, but can contribute to irregular cycles, excessive hair growth, and weight fluctuations.

3 Ways Restrictive Diets Impact Women’s Hormones

Ladies, before you jump into a keto, paleo, vegan, or Whole30 diet, consider the following ways that cutting certain foods out of your diet can affect your hormones.

1. Rise In Cortisol

Many of today’s popular diet trends (namely keto, but paleo and Whole30, too) slash carbohydrates.

Gupta generally suggests a balanced diet that includes all food groups (in moderation). In addition to protein and antioxidant-rich foods, this also includes complex carbohydrates. (Complex carbohydrates—fiber and starch—take longer to digest, are more satiating, and have a more favorable impact on blood sugar compared to simple carbohydrates—like sugar.)

Thing is, many trendy diets require you to cut back on complex carbs—which include whole grains, legumes, and potatoes, explains Brittany Michels, R.D., nutritionist for The Vitamin Shoppe.

Read More: Are You Eating Too Few Carbs?

For women, decreasing carb intake below 15 to 20 percent of your daily calorie intake could cause hormonal trouble, warns Gupta.

“Drastically cutting carbohydrates can cause a rise in cortisol levels,” adds Michels. Though a low-stress body can manage this stress hormone, especially over a short-term period, many women are burdened with many life stressors today. By disrupting cortisol and other hormones, long-term changes in carbohydrate intake can contribute to weight gain, disrupted sleep, fatigue, suppressed immunity, and more, she says.

2. Menstrual Irregularities

Though popular restricted and elimination diets aren’t necessarily low-calorie, people often accidentally cut down on calories when changing the foods they do and do not eat.

“Diets like paleo and Whole30 emphasize whole foods and eliminate many foods not tolerated well,” says Michels. “Women that experience negative hormonal changes during the elimination of these food groups most likely restricted their calories too much.”

Though these diets aren’t designed for you to eat less, if you don’t have replacements ready for the foods you eliminate (or you eat less calorie-dense foods), your overall intake can decrease.

According to the National Institute of Health, low intake of calories can affect the hypothalamus’ ability to release the hormone that starts the menstrual cycle, potentially causing women to experience cycle irregularities or lose her period altogether (called amenorrhea).

That’s why Michels says it’s crucial to replace any eliminated foods with healthy alternatives and check to make sure you’re consuming an appropriate number of calories. Only then can these diets help improve your overall health.

3. Decrease In Serotonin Production

Though various diets (like paleo) can be healthy and effective, you absolutely must manage stress while on a more restricted eating plan, says Michels.

“Someone juggling two stressful jobs, an infant, and a sick parent would not be an ideal for candidate for intermittent fasting, keto, or similar diets,” she warns. In addition to affecting cortisol levels, stress also impacts production of the feel-good hormone serotonin, says Michels.

Even too much exercise, which is technically a stressor, coupled with a restrictive diet can take a toll on the body. “Exercise is one of the healthiest activities you can partake in, but if you live at the gym and are in a constant state of soreness, restricting carbs or protein—like on a keto diet—it can be too much stress on the body,” Michels says.

What I Learned About My Diet And My Hormones

After chatting with experts about the relationship between certain diets and our hormones, I felt validated about my own experience. Now I realize that Whole30’s drastic changes to my already-restricted diet, coupled with daily workouts, may have been quite stressful for my body. (I also definitely didn’t find adequate replacement for the calories I lost by cutting out dairy, soy, and legumes.)

Now, I continue to limit my intake of sugar, dairy, white grains, and soy (I find I feel better when I eat less of them). However, legumes are once again a huge component of my diet—and I feel much more like myself again.

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