Diet and exercise alone aren’t the only things that affect the number on the scale.

You know you might put on extra pounds if you regularly skip barre class or keep selecting M&Ms when you hit up the office vending machine. But if you haven’t changed your eating and exercise habits yet the number on the scale has suddenly crept up, something more could be going on.

Carrying extra pounds isn’t necessarily a problem, of course. But it could signal an underlying medical issue you’ll want to address. Maybe it’s a hormone condition, or a mood disorder, or another factor altering your physiology without you realizing it. The only way to be 100% sure of what it means is to consult your doctor. In the meantime, consider these 8 health-related reasons that might explain why the scale has soared.

An underactive thyroid (hypothyroidism)

Aside from realizing that your jeans are more snug, have you noticed other body changes—like exhaustion, drier skin, or thinner hair? These are all signs of hypothyroidism, a condition in which the butterfly-shaped thyroid gland in your neck isn’t producing enough of thyroid hormone. Your thyroid is kind of a master gland controlling many body functions, so when it’s not working right, symptoms appear throughout your system.

A major function it controls is your metabolism. “Think of your body as a car. You have an engine, and the thyroid hormone maintains the idling of the engine,”  Michael Nusbaum, MD, bariatric surgeon and founder of Healthy Weight Loss Centers, tells Health. “If you’re not producing enough thyroid hormone, your idle gets turned down and you’re not burning as much energy overall.” When your resting metabolism slows, it decreases the amount of calories you burn throughout the day.

One in eight women will develop a thyroid disorder during her lifetime, according to the American Thyroid Association. Dr. Nusbaum says other symptoms to look out for are muscle weakness, constantly feeling cold, bloating, and constipation. If your doctor diagnoses hypothyroidism, you’ll likely be prescribed an oral replacement for thyroid hormone that can alleviate symptoms, including weight creepage, within weeks.

Polycystic ovary syndrome (PCOS

PCOS is another condition caused by out-of-whack hormones. This endocrine disorder is characterized by an imbalance in the sex hormones estrogen and testosterone (women produce testosterone too, though in much smaller quantities than men do). This imbalance leads to irregular periods, acne, and even facial hair growth.

This disorder, which strikes one in 10 women of childbearing age, also disrupts the way the body uses insulin—the hormone responsible for converting carbohydrates into energy, Dr. Nusbaum says. Yep, you guessed it, that means weight gain. When your body becomes insulin resistant, the sugars and starches you consume are stored as fat instead of turned into fuel, he explains.

While there’s no cure for PCOS, women who have it can manage their symptoms with lifestyle changes as well as medication. Your doctor will help you find the method that’s right for you.

Mood disorders like depression and anxiety

Dealing with anxious or sad feelings by mindlessly munching is something almost all of us do on occasion. But either of these mood disorders can make overeating a regular coping mechanism. Dr. Nusbaum gives the example of breaking open a bag of chips, and af
ter three, four, then five handfuls, “you’re not even tasting the chips anymore, your taste buds are completely saturated with the flavor, but you’re still eating, and you’re thinking, Why am I still eating?”

Depression and anxiety can both bring on fatigue, irritability, and a lack of focus. All three can throw you off your game when you work out or lead you to ditch the gym altogether…and pretty soon, pounds pack on.

Reflect on your mood over the past few weeks. If you’ve been consistently down on yourself, on edge, disinterested in things you usually enjoy, or have had trouble sleeping, consider asking your MD for a referral to a mental health professional. A therapist can help get to the bottom of what’s going on, and with proper treatment, help you keep extra pounds at bay.

Perimenopause and menopause

How the five or so years leading up to menopause affects you partially depends on genetics, Dr. Nusbaum says. “I joke around with my patients because they’ll typically come in saying, ‘Holy crap, I’m starting to look like my mother.’” One way to get an idea of the way your body will change during perimenopause and then menopause itself is by asking your mom what changes she noticed in herself. Though your experience could be different than hers, there’s a good chance it’ll be similar—so if she began gaining weight at this point in her life, it could be the explanation for your weight change.

Once again, hormones are to blame for the extra pounds. “The rapid reduction in the amount of hormones present in your body throws you off kilter pretty quickly,” Dr. Nusbaum says. Lifestyle changes can help, so talk to your ob-gyn.

Cushing’s disease

Cortisol is nicknamed the stress hormone, Diondra Atoyebi, DO, family physician at Piedmont Healthcare in Georgia, tells Health; your body releases it in response to overwhelming or dangerous situations. But when your system makes too much cortisol over an extended period of time, you can develop Cushing’s disease. One unpleasant side effect: abnormal fatty deposits in the abdominal area and around the face.

If you’re taking long-term steroids, you’re more likely to develop Cushing’s disease, Dr. Atoyebi says. The condition can also be brought on by tumors on the pituitary gland in the brain, which triggers an uptick in the production and release of adrenocorticotropic hormone—the catalyst that signals the adrenal glands to produce cortisol.