Causes of Sudden Weight Gain

Many people experience minor weight fluctuations of 1-2 kilograms over a few days, which is usually not a cause for concern and can be attributed to lifestyle or dietary changes. However, sudden weight gain—defined as significant weight increase over a short period (weeks or months)—can be alarming. So, what causes sudden weight gain, and when should you see a doctor?

Medical Causes of Sudden Weight Gain

Here are some medical conditions that can lead to sudden weight gain:

• Hypothyroidism

Hypothyroidism is a condition where the thyroid gland does not produce enough hormones, affecting many bodily functions, including metabolism. It slows down metabolism, reducing the calories burned by the body, leading to rapid and sudden weight gain.

• Polycystic Ovary Syndrome (PCOS)

PCOS is a hormonal disorder that causes an imbalance in various hormones, particularly estrogen and male sex hormones known as androgens. Women with PCOS may experience irregular periods, acne, facial hair growth, and insulin resistance, which can lead to sudden and rapid weight gain.

• Depression, Anxiety, and Stress

Some people cope with feelings of anxiety and stress by eating more. Any mood disorder can lead to overeating, and anxiety and stress can also cause fatigue, reduced concentration, and less desire to exercise.

• Heart Failure

Rapid weight gain or swelling in certain parts of the body may result from fluid retention, also known as edema, which can be a sign of heart failure. According to the American Heart Association, a weight gain of more than 1-1.5 kilograms over 24 hours or more than 2.5 kilograms in a week could indicate heart failure.

• Kidney Problems

Sudden weight gain may signal kidney disease since the kidneys are responsible for filtering waste and fluids from the body. If the kidneys are not functioning properly, fluid retention can cause sudden weight gain.

• Cirrhosis of the Liver

In cirrhosis, scar tissue replaces healthy liver tissue, leading to fluid accumulation in the abdomen, weight gain, breathing difficulties, swollen ankles, and abdominal pain.

• Ovarian Cancer

In its later stages, ovarian cancer can cause sudden weight gain, accompanied by other symptoms such as abdominal and pelvic pain, difficulty sleeping, frequent urination, loss of appetite, feeling full quickly, indigestion, and irregular periods.

• Cushing’s Syndrome

This syndrome occurs when the body produces too much cortisol, a hormone that helps the body respond to stress. Cushing’s syndrome causes weight gain, particularly in the abdomen, neck, face, and upper back, while the arms and legs remain thin.

Non-Medical Causes of Sudden Weight Gain

Sudden weight gain doesn't always stem from underlying health problems. It can also result from lifestyle changes. Here are some non-medical causes:

1. Perimenopause or Menopause

A decrease in estrogen levels during menopause or perimenopause can lead to weight gain, particularly around the abdomen.

2. Medications

The side effects of certain medications can also lead to sudden weight gain. Psychiatric drugs, especially antidepressants and bipolar disorder medications, can cause sudden weight gain as they centrally affect the brain and increase appetite unintentionally. Corticosteroids and some types of blood pressure and diabetes medications can also cause weight gain.

3. Lack of Sleep

Sleep deprivation affects hormones that regulate hunger. It raises levels of ghrelin, the hormone responsible for hunger, and lowers levels of leptin, the hormone responsible for satiety. Therefore, chronic insomnia can lead to sudden weight gain.

4. Quitting Smoking

Some people experience rapid weight gain when they first quit smoking. Nicotine in cigarettes and other tobacco products increases metabolism and suppresses appetite, so when a person quits smoking, they may feel hungrier and eat more.

When to See a Doctor

You should see a doctor if you experience:

• Rapid and sudden weight gain over a few days.
• Other symptoms accompanying the weight gain.
• Gradual weight gain over a long period without an apparent cause.

In these cases, your doctor may ask for some tests and analyses after reviewing your medical history to determine the underlying cause. 

Blazma offers all the tests your doctor might request to identify the cause of rapid weight gain, such as kidney function tests, liver function tests, thyroid function tests, cortisol tests, and more.