When you gain or lose weight unexpectedly, you might assume it’s due to inadvertent changes in how you eat or how active you’ve been. And most of the time, that’s probably what’s behind it. But a laundry list of health conditions can also influence weight gain or loss, either by affecting your appetite and energy levels or through other mechanisms. Let’s explore 13 surprising health conditions that can lead to weight changes.
If you’re experiencing prolonged or significant weight gain, it’s worth talking to your doctor to see if you might have one of the following conditions.
Your thyroid is a small but mighty butterfly-shaped gland in your neck, according to the Mayo Clinic. It produces the hormones triiodothyronine and thyroxine to control the rate of different activities in your body that make up your metabolism, like how quickly you burn calories.
Hypothyroidism happens when your thyroid gland doesn’t make enough of these key hormones. This can result in a reduced metabolism that leads to weight gain. Other hypothyroidism symptoms include fatigue, difficulty tolerating cold, joint and muscle pain, constipation, dry skin, thinning hair, decreased sweating, heavy or irregular periods, depression, and a slowed heart rate, according to the Mayo Clinic.
PCOS is one of those gynecologic conditions that may seem simple but is actually quite complex. What’s most important to know is that PCOS is a hormonal imbalance that can cause a wide range of issues including an irregular period, hair growth on body parts like the face, acne, infertility, and weight gain, according to the American College of Obstetricians and Gynecologists (ACOG).
Although researchers are still rooting out the exact cause (or causes) of PCOS, its connection with weight gain seems tied at least in part with insulin resistance, Jessica Shepherd, M.D., a minimally invasive gynecologist at Baylor University Medical Center at Dallas, tells SELF. If you have insulin resistance, it means your body’s cells don’t respond effectively to insulin, a hormone that helps keep your blood sugar stable. It also seems as though gaining a substantial amount of weight can predispose you to developing PCOS, according to the Mayo Clinic. Like we said, it’s complex.
You may already know that depression can lead to weight gain if people eat more than usual to cope with feelings of emptiness and sadness. If you have depression, you may also have a hard time mustering enough energy to do much of anything, which can make being active harder. This can all also happen with persistent depressive disorder (also known as dysthymia), which is when a person experiences prolonged feelings of sadness and lethargy that don’t meet the criteria for major depressive disorder. As SELF previously reported, many people with persistent depressive disorder don’t realize they have it, so any associated weight gain can seem random.
Along with these symptoms, someone with persistent depressive disorder may deal with irritability, feelings of guilt, having a loss of interest or pleasure in hobbies, trouble concentrating, difficulty sleeping, and more, according to the Mayo Clinic.
Insomnia can smash into every aspect of your sleep like a wrecking ball. You might find it impossible to fall asleep or stay asleep, or you might wake up at night and not be able to get back to sleep, the Mayo Clinic says.
There are obvious insomnia symptoms like being hella tired all the time, irritability, difficulty paying attention, and anxiety about sleep. But someone with insomnia may also experience weight gain, board-certified sleep medicine doctor, sleep researcher, and neurologist W. Christopher Winter, M.D., of Charlottesville Neurology and Sleep Medicine, and author of the book, The Sleep Solution: Why Your Sleep is Broken and How to Fix It, tells SELF.
For starters, your circadian rhythm impacts your metabolism, and insomnia can throw them both off. Also, the associated fatigue (and potential depression tied with insomnia) can make it harder to be active, Dr. Winter says. Finally, people also often try to self-treat insomnia by drinking alcohol before bed, he says, which adds excess calories. (Also, although alcohol can indeed make you tired at first, it can prevent you from sleeping deeply and wake you up at night.)
Peptic ulcer disease is so awful you might cringe just reading about it. It happens when sores appear on the lining of the stomach or duodenum (the first part of the small intestine immediately beyond your stomach), the U.S. National Library of Medicine says.
Symptoms include pain that starts between meals or during the night, pain that pauses if you eat or take antacids, pain that lasts for minutes to hours, and pain that comes and goes for several days or weeks, the NIDDK says. You may also deal with uncomfortable bloating or burping, feeling sick to your stomach, vomiting, poor appetite, and weight loss.
“Peptic ulcer disease in and of itself does not lead to weight changes, but eating habits may change in an attempt to deal with the pain associated with peptic ulcer disease,” Elizabeth Lowden, M.D., a bariatric endocrinologist at Northwestern Medicine Regional Medical Group, tells SELF. “Some may find they overeat or eat more frequently as that helps with the abdominal pain,” which can lead to weight gain.
This disorder occurs when your body makes too much of the hormone cortisol over a long period of time, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Although cortisol is notorious for driving up your stress, this hormone has other tasks on its docket, including regulating the way you metabolize food, the Mayo Clinic says. So, when you produce too much of it, it can interfere with your metabolism and cause you to gain weight, Peter LePort, M.D., a bariatric surgeon and medical director of Memorial Care Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California, tells SELF.
Beyond weight gain, symptoms of Cushing syndrome include deposits of fat-based tissue at the midsection, upper back, face, and between the shoulders, stretch marks due to rapid weight gain, thinning skin prone to bruising, increased body hair, irregular or missing periods, and more, according to the Mayo Clinic.
This happens when your heart can’t pump enough blood to meet your body’s needs, the U.S. National Library of Medicine explains. As a result, blood and fluid can build up in your feet, ankles, and legs, which can cause swelling and rapid weight gain. Your abdomen may swell as well, (the Mayo Clinic says) says. Blood and fluid can also back up into your lungs, leading to fatigue and shortness of breath.
Other symptoms of congestive heart failure include a rapid or irregular heartbeat, a persistent cough or wheezing with white or pink phlegm, an increased need to pee at night, difficulty concentrating, and chest pain, according to the Mayo Clinic.
Sure, sometimes there’s a simple, non-concerning explanation for your weight loss. But if your lifestyle is the same and you’re still losing weight, it’s time to ask your doctor about whether or not you might have one of the following conditions.
As you might have guessed, hyperthyroidism is basically the opposite of hypothyroidism: Instead of your thyroid gland being underactive, it’s overactive. Having too much of those thyroid hormones circulating can kick your metabolism into overdrive and make you lose weight, Dr. LePort explains.
Other symptoms include nervousness or irritability, fatigue or muscle weakness, feeling too hot, problems sleeping, shaky hands, a rapid and irregular heartbeat, diarrhea, and mood swings, the NIDDK says.
Just as this condition can cause weight gain due to overeating, it can also cause weight loss due to undereating. If you’re grappling with this and other symptoms of persistent depressive disorder or depression, that’s definitely worth noticing.
Like the condition above, this is on both lists because it can influence your eating habits in a number of ways. Some people find that eating actually makes the pain of peptic ulcers worse, Dr. Lowden says, so they might try to eat as little as possible and lose weight as a result.
You might already know that type 1 and type 2 diabetes happen when your blood sugar (glucose) levels are persistently too high, and that diabetes is often associated with obesity.
But diabetes can also cause weight loss, according to the Mayo Clinic, along with issues like increased thirst, peeing often, fatigue, blurry vision, and more. The weight loss comes into play if diabetes makes you pee frequently to get rid of excess sugar in your blood, which can also make you pee out calories, the Mayo Clinic explains.
When you have celiac disease, eating gluten (a protein that’s found in wheat, barley, and rye) triggers a pretty gnarly immune response in your small intestine, according to the Mayo Clinic. Over time, this harms your small intestine’s lining and prevents absorption of nutrients, which can lead to weight loss.
This intestinal damage can also cause diarrhea, fatigue, bloating, anemia, and more, the Mayo Clinic says.
This actually isn’t a condition, it’s a collection of symptoms. If someone has dementia, neurological changes compromise their ability to think, remember, and reason as well as they used to, the National Institute on Aging explains. So, if someone has a form of dementia such as Alzheimer’s disease, they’ll go through behavioral and personality changes, along with other potential issues like unintended weight loss.
“They may simply forget to eat,” Dr. LePort says. “It may not even register sometimes that they’re hungry, or they don’t know what to do to resolve the issue.” They may also experience reduced smell and taste, trouble swallowing, and distraction while eating, according to the Mayo Clinic—all of which can contribute to weight loss.
Inflammatory bowel disease is a catch-all term for disorders that cause persistent inflammation in your GI system, the Mayo Clinic explains.
One of those disorders is Crohn’s disease. It causes hellish inflammation, typically in the last part of the small intestine and the colon, though it can affect any part of the GI tract, the Mayo Clinic explains. The inflammation frequently spreads deep into the layers of the bowel tissue. Then there’s ulcerative colitis, which is when you have inflammation and ulcers in the lining of your large intestine and rectum, the Mayo Clinic says.
Either type of inflammatory bowel disease can lead to symptoms like abdominal pain, severe and bloody diarrhea, fatigue, mouth sores, and a reduced appetite. Unsurprisingly, if you’re dealing with these symptoms, you’re probably going to lose weight, Dr. LePort explains.
This lesser-known disorder happens when your adrenal glands don’t produce enough of the hormones cortisol and aldosterone, the Cleveland Clinic says. These hormones influence almost every organ and tissue in your body, according to the Mayo Clinic, and signs that something’s up with them include abdominal pain, abnormal periods, cravings for salty foods, dehydration, depression, diarrhea, loss of appetite, nausea, sensitivity to cold, vomiting, and unexplained weight loss.
The weight loss occurs due to a portion of your adrenal glands called your cortex, the Mayo Clinic explains. The cortex is the outer layer of these glands, and it produces a group of hormones called corticosteroids. Corticosteroids include glucocorticoids, which influence your body’s ability to convert fuel from the food you eat into energy. Without sufficient glucocorticoids, your body has trouble properly utilizing the nutrients you eat, which can lead to weight loss. (As can the nausea, vomiting, and loss of appetite.)
It’s normal for your weight to fluctuate a bit from day to day, or even from morning to night. But a fluctuation that keeps you in a general weight range is different from persistent weight gain or loss over time. If that’s what you’re noticing, it’s time to head to a doctor. That’s especially true if you’re dealing with significant weight changes along with any of the above additional symptoms indicating that something’s wrong.