Gaining weight when you are not trying to do so can have many causes.
Metabolism slows down as you age. This can cause weight gain if you eat too much, eat the wrong foods, or do not get enough exercise.
Drugs that can cause weight gain include:
- Birth control pills
- Some drugs used to treat bipolar disorder, schizophrenia, and depression
- Some drugs used to treat diabetes
Hormone changes or medical problems can also cause unintentional weight gain. This may be due to:
- Cushing syndrome
- Underactive thyroid, or low thyroid (Hypothyroidism)
- Polycystic ovary syndrome
Bloating, or swelling due to a buildup of fluid in the tissues can cause weight gain. This may be due to menstruation, heart or kidney failure, preeclampsia, or medicines you take. A rapid weight gain may be a sign of dangerous fluid retention.
If you quit smoking, you might gain weight. Most people who quit smoking gain 4 - 10 pounds in the first 6 months after quitting. Some gain as much as 25 - 30 pounds. This weight gain is not simply due to eating more.