N
The Global Insight

Why am I suddenly gaining weight?

Author

John Johnson

Updated on March 09, 2026

It’s often due to fluid retention, abnormal growths, constipation, or pregnancy. Unintentional weight gain can be periodic, continuous, or rapid. Periodic unintentional weight gain includes regular fluctuations in weight. One example of unintentional weight gain is experienced during a woman’s menstrual cycle.

What hormone causes sudden weight gain?

Ghrelin helps stimulate appetite and increase fat deposition. It is mainly secreted by the stomach, as well as the small intestine, pancreas, and brain. Elevated levels of ghrelin in the blood can lead to weight gain. Obese people are particularly sensitive to ghrelin, encouraging them to eat more.

Do any cancers cause weight gain?

. People with certain kinds of cancer might have swelling in the abdomen (belly) that causes weight gain. Or, sometimes you gain weight because certain anti-cancer drugs cause your body to hold on to extra fluid.

Why am I putting on weight when I’m eating less?

A calorie deficit means that you consume fewer calories from food and drink than your body uses to keep you alive and active. This makes sense because it’s a fundamental law of thermodynamics: If we add more energy than we expend, we gain weight. If we add less energy than we expend, we lose weight.

What stomach problems cause weight gain?

Digestive conditions such as Crohn’s disease or ulcerative colitis are often treated with steroids; steroid use can cause weight gain. Also, patients with GERD (gastroesophageal reflux disease) or PUD (peptic ulcer disease) often feel better when there is food in their stomach to soak up excess acid.

Why do I keep gaining weight even though I don’t eat much?

Poor sleep, sedentary activities, and eating too many processed or sugary foods are just some of the habits that may increase your risk of weight gain. Yet, a few simple steps — such as mindful eating, exercise, and focusing on whole foods — can help you reach your weight loss goals and improve your overall health.

What autoimmune disease makes you gain weight?

Type 1 diabetes, which is mostly detected at a younger age is another autoimmune condition that may lead to weight gain. In this condition, the pancreas is unable to produce insulin, leading to a spike in the blood sugar level. Insulin plays a major role in directing the body how to use and store glucose for energy.

Can leukemia cause weight gain?

Some children with acute lymphoblastic leukemia (ALL) may become overweight. They are at most risk of gaining weight during their treatment and up to one year after finishing it.

Can blocked lymph nodes cause weight gain?

A sluggish lymphatic system has been linked to cellulite and fat deposits. When toxins are trapped overtime in the body they lead to small pockets of fat and overtime the accumulation can cause weight gain and even obesity!