13 Health Conditions That Can Make You Gain Weight

There’s nothing more frustrating than realizing you’re gaining weight. Sometimes it’s not your fault. Unexplained weight gain can actually be a side effect of an underlying health condition you may not know you have. A doctor can help diagnose and treat these issues, which will get your weight back on track.

1. Cushing’s syndrome

female feet on a weighing scale

Though it’s not likely you have it, Cushing’s syndrome can lead to weight gain. | iStock.com

  • How many diagnosed: about 3 in 1 million Americans annually
  • Other symptoms: acne, high blood pressure, muscle weakness

Caused by unusually high cortisol levels, Cushing’s syndrome is more serious than the average weight-related issue, says Healthline. Depression, stress, and even some medications can cause the stress hormone to elevate. Your chances of being diagnosed are extremely rare. However, if the symptoms seem familiar, check with a medical professional; Cushing’s can be fatal if left untreated.

Next: Have you heard of this kind of tumor?

2. Prolactinoma

Man unable to close pants

Benign tumors can cause weight gain. | iStock.com

  • How many diagnosed: about 1 in 10,000 Americans
  • Other symptoms: reduced sex drive, headaches, vision disorders

These benign tumors develop in your pituitary gland, the area of your brain that secretes a hormone called prolactin, according to Livestrong.com. Though prolactinomas aren’t cancerous, these tumors cause your pituitary gland to produce more of the hormone, resulting in unwanted weight gain.

According to Mayo Clinic, in some cases, long-term medication is enough to treat prolactinomas. Your doctor might also recommend surgery to remove the tumor, which also fixes the problem.

Next: A mental health condition with highs and lows

4. Bipolar disease

Sad man

The depressive stage of bipolar disease can involve overeating. | Source: iStock

  • How many diagnosed: about 5 million U.S. adults
  • Other side effects: spending sprees, unprotected sex, drug use, deep sadness, loss of energy, sleeping too much or too little

You can mark this mental illness by observing extreme mood shifts, like depression and mania. Depression caused by bipolar lasts at least two weeks, according to Healthline. During this time, the person may overeat, causing weight gain. Although bipolar disease can make everyday life difficult, medication and therapy can alleviate the frustrating symptoms.

Next: A broken heart affects your feelings — and your figure.

2. Congestive heart failure

Middle-aged businessman suffering chest pains

Weight gain can occur at the beginning stages of congestive heart failure. | iStock.com/mheim3011

  • How many diagnosed: 5.7 million adults in the U.S.
  • Other symptoms: joint swelling, excessive urination, irregular heartbeat, wheezing,

This chronic progressive condition hurts your heart muscles, causing the organ to pump inefficiently. When this happens, fluids back up inside your liver, lungs, abdomen, or lower body. Notably, weight gain is one early symptom of congestive heart failure. Annual checkups will help your doctor check for heart problems like hypertension, coronary artery disease, and valve conditions; they can all cause congestive heart failure.

Next: How you handle anxiety is key.

10. Generalized anxiety disorder

nervous stressed young woman

Generalized anxiety disorder can lead to overeating. | iStock.com/SIphotography

  • How many diagnosed: 6.8 million adults, or 3.1% of the U.S. population
  • Other symptoms: fear, hypervigilance, lack of concentration, difficulty falling asleep, palpitations

Everyone feels stressed from time to time. Generalized anxiety disorder, however, goes beyond the occasional nervousness. According to the Anxiety and Depression Association, those with GAD face constant tension and worry, even if you know it’s irrational. Chronic stress produces more stress hormones, and heightened cortisol levels encourage your body to hold onto fat. You could also experience more intense food cravings.

Both medication and talk therapy can help you manage GAD symptoms, especially if your first response to a stressful situation is to eat all the chocolate you can find.

Next: There’s no cure for this disease, but you can manage it and lose some pounds.

9. Hypothyroidism

human thyroid gland

A sluggish thyroid will stall your metabolism. | iStock.com/Nerthuz

  • How many diagnosed: approximately 10 million Americans
  • Other symptoms: fatigue, brittle nails, dry skin, sensitivity to cold, sexual dysfunction

The hormone your thyroid produces controls your metabolism. But the Mayo Clinic says when your thyroid stops creating enough hormone, your metabolism slows. This condition, hypothyroidism, often causes weight gain. Since these symptoms are common in conditions like depression, your doctor can check your hormone levels to rule out thyroid issues. A prescribed oral medication can correct thyroid issues and get your metabolism back to normal.

Next: A hidden battle in your body

3. Hashimoto’s disease

Man with lower back pain

Lower back pain is an odd but common symptom of Hashimoto’s. | Tom Merton/Getty Images

  • How many diagnosed: about 14 million Americans
  • Other symptoms: constipation, hoarse voice, high cholesterol, lower body muscle weakness, feeling sluggish, thinning hair

This autoimmune disease makes white blood cells and antibodies mistakenly attack the cells of your thyroid, causing weight gain and other issues. Although the cause of Hashimoto’s isn’t clear, explains Healthline, some scientists think it’s genetic. Symptoms may not appear for years, and heart problems, anemia, or high cholesterol could develop if the disease is left untreated.

Next: Overeating is common with this uncomfortable condition.

5. Gastroesophageal reflux disease

close-up of a man clutching his chest to show a heart attack

Since certain foods can relieve heartburn, many people with this condition end up overeating. | iStock.com

  • How many affected: an estimated 15-30% of the U.S. population
  • Other symptoms: heartburn, belching, difficulty swallowing, tooth erosion

Gastroesophageal reflux disease causes the muscle between the esophagus and stomach to relax, according to WebMD, allowing stomach contents to flow back into your esophagus (gross). Resulting in painful heartburn, the condition itself isn’t what causes people to gain weight.

The added pounds come from people overeating to temporarily reduce the effects of GERD, says Redbook. Food and saliva can counteract stomach acid in your esophagus, but it won’t last. Eating to temporarily relieve pain is nearly guaranteed to cause weight gain. Dietary and lifestyle changes, and sometimes medications, can improve GERD symptoms and prevent overeating.

Next: This is one irritating condition.

7. Irritable bowel syndrome

man sitting on the bad, clutching his stomach

IBS can also lead to weight loss, but most people overcompensate on days when they feel good. | iStock.com

  • How many diagnosed: about 20% of the U.S. population
  • Other symptoms: bloating, abdominal pain, change in bowel habits

According to Healthline, irritable bowel syndrome is a GI disorder that causes pain and discomfort. Symptoms often occur in flares, meaning some days you won’t feel well and subsequently won’t eat much. On days you feel better, though, those with IBS can overeat, which will cause weight gain. Livestrong.com suggests high-fiber foods and exercise to relieve uncomfortable IBS symptoms, while red meat and caffeine trigger it.

Next: Your emotional and physical health can both be compromised with this disorder.

8. Persistent depressive disorder

Sad woman on the bed with husband in background

This depression disorder can cause a change in eating habits. | iStock.com

  • How many diagnosed: between 25 and 45 million Americans
  • Other symptoms: ongoing sadness, feelings of hopelessness, changes in sleep

Persistent depressive disorder, a milder type of chronic depression, can wreck both your emotional and physical health. According to Healthline, those diagnosed often experience changes in appetite, making overeating more probable. If you often eat when you’re sad, a combination of medication and ongoing therapy can help you learn to cope with your feelings.

Next: This one only affects women.

11. Polycystic ovarian syndrome

Fitness concept and welfare with female athlete joggin in city park

Lifestyle changes can help with PCOS. | iStock.com/Bogdanhoda

  • How many diagnosed: 1 in 10 women of childbearing age
  • Other symptoms: ovarian cysts, abnormal menstruation, acne, depression, unwanted hair

Like hypothyroidism, polycystic ovarian syndrome is a health condition caused by a hormonal imbalance. Mayo Clinic says women must have at least two symptoms to receive a PCOS diagnosis. Unfortunately, many women with PCOS gain weight. If you experience irregular periods and unexplained weight gain, check with your doctor.

Next: Blame the aging process for this.

12. Menopause

elderly couple

Menopause can cause weight gain. | iStock.com

  • How many diagnosed: For women, the onset of menopause begins, on average, at 51 years old.
  • Other symptoms: night sweats, osteoporosis, hot flashes, insomnia, loss of hair, moodiness

Maintaining a healthy weight becomes more difficult as you age. Unfortunately, weight gain is much more common — and happens faster — in women over 50. Mayo Clinic explains the hormonal changes women experience during menopause can put on extra pounds, particularly in the abdomen. Eating right, exercising, and getting enough sleep are especially valuable for women experiencing this life stage.

Next: Pregnancy obviously leads to weight gain, but this accelerates it.

13. Gestational diabetes


Pregnant woman holding belly

Gestational diabetes can cause excess weight gain for pregnant women. | iStock.com/tamaravidmar

  • How many diagnosed: 6-8% of pregnant women
  • Other symptoms: excessive hunger or thirst and/or excessive urination

Most of us are familiar with types 1 and type 2 diabetes. Did you know there’s a third type, called gestational diabetes? According to HealthCentral, non-diabetic women can develop this type during their fifth or sixth month of pregnancy. During this time, the body produces enough insulin, but hormones made in the placenta block the effect it’s supposed to have on blood sugar.

The good news is, gestational diabetes typically disappears after the baby is born. If you’re pregnant and gaining more weight than you should, check with your doctor to receive proper treatment.

Additional reporting by Lauren Weiler and Meg Dowell