Why Am I Gaining Weight So Fast?

Something more could be going on if you haven't changed your eating and exercise habits and are still gaining weight fast. Possible causes include anxiety and depression, hormonal disorders, insomnia, and certain medications.

Carrying extra pounds isn't necessarily a problem, but it could signal an underlying health concern you'll want to address. The only way to be entirely sure of what it means is to consult a healthcare provider. Consider these eight health-related reasons you might be gaining weight so fast.

1. Underactive Thyroid (Hypothyroidism)

Aside from sudden weight gain, have you noticed other body changes like exhaustion, drier skin, or thinner hair? These are all signs of hypothyroidism, in which the butterfly-shaped gland in your neck isn't producing enough hormones. The thyroid controls many body functions. Symptoms appear throughout your body so when it's not working right.

The thyroid controls metabolism, a major function. If your thyroid is not producing enough hormones, you will not burn as much energy overall. The number of calories you burn decreases when your resting metabolism slows.

Other symptoms to look out for include muscle pain, constantly feeling cold, and constipation. You'll likely need an oral replacement for thyroid hormone if a healthcare provider diagnoses hypothyroidism. This medication can alleviate symptoms within weeks.

2. Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is another hormonal disorder. PCOS is characterized by an imbalance in levels of estrogen and male sex hormones called androgens. This imbalance leads to irregular periods, acne, and even facial hair growth.

PCOS, which affects one in 10 women of childbearing age, also disrupts the way the body uses insulin. This hormone is responsible for converting glucose (sugar) into energy. If your body becomes insulin-resistant, the sugars and starches you consume are stored as fat instead of turned into fuel.

There's no cure for PCOS, but you can manage symptoms with lifestyle changes and medications. A healthcare provider will help you find the right method for you.

3. Depression and Anxiety

Dealing with anxious or sad feelings by snacking is something many people occasionally do. Either of these mood disorders can make overeating a common coping mechanism. Depression and anxiety can also bring on fatigue, irritability, and a lack of focus. These symptoms can affect how often you feel like exercising.

Reflect on your mood over the past few weeks. Consider reaching out to a mental health specialist if you've been consistently down on yourself, on edge, disinterested in things you usually enjoy, or having trouble sleeping. They can help you figure out what's causing your symptoms and advise treatments to help you maintain a healthy weight.

4. Perimenopause and Menopause

A drop in estrogen levels during menopause and perimenopause (the years leading up to menopause) can cause weight gain. This extra weight tends to accumulate in the abdominal area. Abdominal fat increases the risk of heart disease and high blood pressure. Eating a nutrient-rich diet and regularly exercising can help manage weight gain. 

5. Cushing's Syndrome

Cortisol, or the stress hormone, is what your body releases in response to overwhelming or dangerous situations. You can develop Cushing's syndrome when your system makes too much cortisol over an extended period. One side effect Is abnormal fatty deposits in the abdominal area and around the face.

You're more likely to develop Cushing's syndrome if you're taking long-term steroids. 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. This hormone signals the adrenal glands to produce cortisol.

Weight gain, especially in the upper body, is a hallmark sign of Cushing's syndrome. Other symptoms include stretch marks and easy bruising. You can treat Cushing's syndrome in various ways, depending on the cause. A healthcare provider will help you determine what treatment best suits you.

6. Ovarian or Uterine Tumor

A case report published in 2018 detailed the case of a 53-year-old in Singapore who had a 61-pound tumor removed from their uterus after showing up at the hospital struggling to breathe. The tumor was likely developing inside their body for years to grow so large.

It's an extreme case, but the case report shows that large pelvic area tumors, such as uterine or ovarian tumors, can distend the abdomen the way excess fat does if untreated. The tumor was benign in the case of the Singaporean person, but others can be cancerous.

Other symptoms of ovarian or uterine tumors include lower back pain, vaginal bleeding, painful intercourse, and constipation. These signs are common for other conditions, so consult a healthcare provider to confirm the root cause of the problem. They can help determine what treatment best suits you.

7. Medications

Ask a healthcare provider if gaining weight is a possible side effect before starting any new over-the-counter (OTC) or prescription medication. Psychiatric medications, especially for depression and bipolar disorder, commonly cause weight gain. These drugs act centrally on the brain and inadvertently increase your desire to eat.

Medications that treat high blood pressure, as well as taking insulin for diabetes, can also cause weight gain. Staying active and eating a balanced diet can help you manage the disease without adding excess weight.

8. Insomnia

You might turn to snack on simple carbs—chips, cookies, candy—to give you quick energy boosts to get through the day. Why does exhaustion trigger cravings like these? 

A lack of sleep affects your hunger-regulating hormones. After a restless night, levels of ghrelin, a hormone that tells your body it's time to eat, increase. Leptin, the hormone that signals fullness, may also plunge. This doesn't just happen overnight; persistent insomnia causes weight gain.

Sleep deprivation can also affect your decision-making. When you're tired, you become more impulsive, which can coax you into eating more. Sugar is instant energy, something your body will crave when you're exhausted.  

Having a cookie doesn't immediately make you gain weight. However, if your habit is to choose sugary foods over more nutrient-dense options, you may find you are gaining weight.

A Quick Review

There are many possible causes of rapid weight gain, including anxiety and depression, insomnia, certain medications, and hormonal disorders like polycystic ovary syndrome (PCOS).

A healthcare provider can help you determine the cause of your sudden weight gain. Making a diagnosis is important for figuring out if you have an underlying condition and finding the right treatment plan.