Weight gain after menopause can be due to many factors such as -
Hormonal imbalance

Lifestyle factors

Psychological factors

Genetic factors

Age factor

Rare and less frequent factors causing weight gain after menopause-

Hypothyroidism

Hypoglycemia

Cushing’s syndrome

Hormonal Imbalance -

Estrogen - It is the female sex hormone which is responsible for monthly ovulation. During menopause the estrogen levels decline rapidly. As the ovaries produce less estrogen, the body looks for alternate sources of estrogen. The fat cells in the body can produce estrogen, so the body takes measures to convert the calories into fat cells. The fat cells don’t burn calories like muscle cells and this leads to accumulation of fat and the extra weight.

Progesterone - Post menopause even the progesterone levels decrease. This leads to water retention and bloating. So it is also responsible for weight gain.

Androgen- Higher levels of androgen are responsible for accumulating the extra weight around the abdominal area. This hormone changes the shape of the body from pear-shaped to apple-shape.

Testosterone - Testosterone levels also decrease. Testosterone helps the body create lean muscle mass from the calorie intake. The muscle cells increase metabolism by burning more calories than the fat cells. So when the testosterone level drops, it lowers the body’s metabolism and the body utilizes lesser calories.

Insulin - In the post menopausal period women may develop insulin resistance leading to Type 2 diabetes.

Lifestyle Factors-

Diet and exercise play an important role in preventing the weight gain post menopause. Lack of exercise maybe responsible for the weight gain.

Psychological Factors-

Anxiety, depression, stress, overwork, fatigue can also contribute to weight gain in menopause. Psychological factors lead to an imbalance in the metabolism which eventually causes weight gain.

Genetic Factors -

Women whose parents or close relatives have shown a weight gain tendency after menopause are more likely to gain weight after menopause.

Age Factor-

The lean muscle mass in the body naturally diminishes with age. If the muscle loss is not replaced then the body composition will shift to more fat and less muscle mass. This slows down the rate of metabolism. If there are no dietary changes then the woman is more likely to gain weight.