Most people experience fluctuations in their weight, and it is common to gain weight over time. However, if a person gains weight in a very short time without a clear reason, this could be a sign of an underlying health condition. When weight gain is not related to a health condition, common causes include:
- Eat more
- Perimenopause and menopause
- Metabolism slows with age
- Be less physically active
- Water retention due to dehydration or excess salt
- Stress, depression, or anxiety
- Lack of sleep
Anyone experiencing rapid weight gain that is not due to one of the above causes or that affects her quality of life should see a doctor.
Certain medications can make people gain weight quickly. According to the Obesity Action Coalition, some medications can cause people to gain up to several pounds a month as a side effect.
Medicines that can make people gain weight quickly include some medicines that treat:
- Mellitus diabetes
- High blood pressure
- Depression and psychiatric disorders
It is essential not to stop taking a medicine without first consulting a doctor.
Research has shown that lack of sleep can lead to weight gain. Changes in sleep cycles can affect eating patterns and mood, causing people to overeat. The authors of one study found that sleep-deprived people ate more carbohydrates than necessary to meet their energy needs, leading to weight gain. Participants in the same study also consumed more calories overall, especially after dinner.
3. Stop smoking
Some people initially gain weight when they quit smoking tobacco products. Experts believe this occurs both because nicotine suppresses appetite and because withdrawal symptoms can include stress, which can lead to overeating.
Research has shown that 1 kilogram (kg) is the average weight gain in the first month after quitting smoking. Most of a person’s weight gain appears to occur during the first 3 months after quitting, and the rate of weight gain appears to decrease by 6 months.
However, changes in weight as a result of quitting smoking can vary from person to person. The same research found that 16 percent of people lost weight in the first year without smoking, while 13 percent gained more than 10 kg.
4. Polycystic ovary syndrome
People with polycystic ovary syndrome (PCOS) may find that they easily gain weight around their waist. PCOS causes the ovaries to produce abnormally high levels of male hormones. Other symptoms of PCOS include:
- Irregular periods
- Excess hair on the back, chest, or abdomen
- Hair thinning or hair loss
- Dark patches of skin around the armpits, breasts, or neck
Although there is no cure for PCOS, a doctor may recommend lifestyle changes, such as getting more exercise and eating a healthy diet, that can reduce symptoms. Hormonal medications can also help control symptoms.
5. Heart failure
Rapid weight gain or swelling in particular areas of the body can be due to fluid retention and can be a sign of heart failure. According to the Heart Association, a weight gain of more than 2 to 3 pounds (lb) over 24 hours or 5 pounds in a week could be a sign of heart failure.
However, it is vital to keep in mind that a person’s weight generally fluctuates a few pounds over the course of a day. If their weight returns to normal and they have no additional symptoms, the temporary increase could be due to normal bloating and fluid retention. If blood flows slowly to and from the heart, it affects the function of other major organs in the body. As a result, the fluid accumulates in the tissues, which causes weight gain and bloating.
People may experience weight gain with swelling in the:
- Stomach area
Other signs and symptoms of heart failure include:
- Fluid that builds up inside the lungs (pulmonary edema)
- Frequent cough
- Feeling out of breath when resting
- Dizziness or confusion
- Loss of appetite
- Difficulty sleeping or lying down
If people experience any of these symptoms along with rapid weight gain or unexplained swelling, they should seek medical attention.
6. Kidney problems
Sudden weight gain or swelling in the body could be a symptom of kidney disease, such as kidney failure or nephrotic syndrome, which is damage to the kidneys.
If the kidneys are not working properly, the body can retain fluid, resulting in weight gain. Damaged kidneys cannot remove wastes and fluids from the body properly, so they accumulate in the tissues. Swelling due to kidney problems usually affects the legs, ankles, or feet.
Other symptoms that may indicate a problem with the kidneys include:
- Don’t urinate a lot
- Urine that looks foamy
- Loss of appetite
- Muscle cramps
- Joint pain
Trouble concentrating or confusion
If people experience rapid weight gain and their abdomen looks enlarged, this may indicate cirrhosis. Cirrhosis is a condition in which scar tissue replaces healthy tissue in the liver and can cause fluid to build up in the abdominal cavity. This abnormal accumulation of fluid is called ascites.
Other symptoms of cirrhosis include:
- Swollen ankles
- Breathing difficulties
- Abdominal pain
If people are already receiving treatment for ascites, they should contact their doctor if they gain more than 2 lbs. Per day for 3 days in a row.