It’s natural for your weight to fluctuate throughout the year. Maybe you eat a bit too much during the holidays and gain a bit of weight, or you come down with the stomach flu and end up dropping a few pounds—a slight swing on the scale is normal and nothing to worry about.
But if you drop at least five percent of your body weight in less than six months—and you can’t pinpoint a good explanation for that weight loss—it’s time to let your doctor know what’s up, says Anne Cappola, MD, an endocrinologist and professor of medicine at the University of Pennsylvania. That means if you’re 150 pounds, a weight fluctuation of about seven or eight pounds in a short amount of time should be a red flag.
Here, health issues that could explain why you’re losing weight so suddenly.
You have an over-active thyroid
Weight loss is a common symptom of hyperthyroidism—or an over-active thyroid, Dr. Cappola says. This means your thyroid—the butterfly-shaped gland in your neck that helps regulate your metabolism and growth—is pumping out too many hormones, resulting in a slew of body changes.
“If I suspected a thyroid issue, I’d probably look for increased hunger or heart palpitations,” she explains. Sleeping problems or feeling hot all the time are also common symptoms of an over-active thyroid, she says.
You’re not eating enough
Dr. Hildreth mentions something experts refer to as the “obesity paradox.” Later in life, weight loss—not weight gain—is associated with a greater risk of death. “As we age, the stomach empties more slowly, which makes you feel fuller longer,” she says. “Also, some of the brain signals that control appetite and fullness become attenuated,” Dr. Hildreth adds. All of this can lead to older adults eating less, losing weight, and failing to get enough nutrients to support their bodies’ needs. Be sure you’re eating enough protein to help your body carry out important bodily functions, like curbing hunger, stabilizing blood sugar, and building muscle mass—which people lose as they get older. “Many medications can also affect your appetite, so you need to pay attention to how much and how often you’re eating,” Dr. Hildreth adds.
You have celiac disease
Celiac disease—an autoimmune disorder in which ingesting gluten causes damage to the small intestine—can lead to a drop in weight, and tends to be accompanied by other GI symptoms like bloating and diarrhea, says Jamile Wakim-Fleming, MD, a gastroenterologist at Cleveland Clinic.
Why? If you have celiac disease and eat gluten, your immune system freaks out a bit. This reaction can mess with the lining of your small intestine, hampering its ability to help you absorb nutrients properly, according to the Mayo Clinic. Inflammatory bowel diseases like Crohn’s disease can also result in unexplained weight loss due to malabsorption as well.
You’re struggling with depression
You’ve developed diabetes
“Especially early on, new-onset diabetes can cause weight loss,” Dr. Cappola says. You may also feel crazy thirsty and notice you’re peeing all the time. “Your body is literally peeing out glucose because you can’t absorb it, and that drives thirst,” she explains. Diabetes also causes your body to suck nourishment from your muscles, which fuels the sudden weight drop.
It may be cancer
Several types of cancer, as well as a tumour or ulcer in your stomach or intestines, can cause inflammation or malabsorption issues that may lead to a drop in weight, Dr. Wakim-Fleming says. “If someone comes to me with unexplained weight loss, I’ll check their stomach and colon and bowels for tumours or inflammation,” she says. “I’ll als0 look for tumours in the esophagus”—the tube that connects your throat and stomach—“which can make it hard to swallow.”