It’s hard enough keeping a healthy weight by eating right and getting enough exercise. So seeing the number on the scale change (when nothing else has) can be extremely frustrating. What might lie at the root of mystery weight gain? Unfortunately — or interestingly, depending on how you look at it — several other factors could play a role, even when diet and exercise are well in hand. Here are six possibilities beyond the usual suspects.

woman on scale

1. Sleep Problems: Not getting enough sleep doesn’t just make you groggy and cranky. Repeated studies have shown that chronic insomnia can have major effects on weight. Lack of shut-eye disrupts the endocannabanoid system, which regulates signals related to appetite and the brain’s reward system. This means when you’re tired, you’re more likely to eat more (though you may not even realize you’re doing so). Plus, since lack of sleep leads to daytime fatigue, you may be less active, burning fewer calories. The answer to unintended weight gain, then, may mean going back to bed instead of going to the gym. (And we’re not mad about it.) 

2. Stress: We’ve all been there from time to time, drowning our sorrows with a carton of Ben & Jerry’s or a pan of brownies after a rough day. But believe it or not, even when stress doesn’t actually make you eat more, the hormones it releases into your system can predispose you to hold on to weight. Chronically elevated cortisol increases blood sugar (upping the risk of type 2 diabetes) and puts you at risk of developing more belly fat. For both your physical and mental health, take stress down a peg whenever you can through meditation and good self-care. 

3. Medications: Sometimes the answer to inexplicable weight gain is right behind your medicine cabinet door. Take a look back to where weight started to creep on. Can you correlate it with beginning a new medication? According to WebMD, as much as 15 percent of weight issues are related to meds. Though birth control often gets a bad rap in this area, studies show it’s actually not as likely to cause weight gain as you might think. Instead, antidepressants, steroids, allergy pills, and medications for diabetes and heart disease are more often at fault. If you suspect a medication is fueling a struggle with weight, consult your medical professional.

4. Underlying Health Conditions: For its small size, your thyroid — the butterfly-shaped gland on your neck — holds a lot of power over your weight. When thyroid hormones get too low in a condition called hypothyroidism, metabolism slows way down, leading to unintentional added pounds. And while thyroid problems are probably the most common health issue behind mystery weight gain, they’re by no means the only possible culprit. Polycystic Ovary Syndrome (PCOS), Cushing’s syndrome (a rare adrenal gland disorder), or even (eek!) tumors can mess with the body’s ability to regulate weight. We’re not saying you have a tumor, but if weight gain persists when diet and exercise truly haven’t changed, it’s worth a visit to your doctor for a workup. 

5. Hormone Fluctuations: Ever notice an uptick on the scale just before your period? It’s totally normal. A spike in estrogen can cause the body to retain fluid at the tail end of your cycle. So if your pants feel tighter that time of the month, give it a little time. Quite likely your weight will return to normal within a few days. For some women, however, hormones continue to go haywire even after Aunt Flo has left the building. Low estrogen can trigger fluctuations in blood sugar and, ultimately, weight gain. Talk to your doctor about achieving hormonal balance. It may bring your metabolism back into balance as well.

6. Aging: Ugh, could weight gain simply be the result of getting older? Sadly… yes. While no one likes to hear it, the truth is that the body requires less energy (AKA fewer calories) the older we get. With every decade of age, we tend to move a little less, lose a little more muscle, and have a slower metabolic rate. So even if you haven’t perceived a change to your activity level or diet, more birthdays could mean more weight. To combat this metabolic slow-down, try to incorporate even a little more movement throughout the day (a lunchtime walk or a few squats during Dancing With the Stars never hurt) and focus on a diet of nutrient-dense foods, rather than empty calories.

 Ever dealt with mystery weight gain? Tell us about it at @BritandCo.

(Photo via Getty)