Late night snacking and poor sleep too can cause weight
gain. Polycystic ovary too causes weight
gain, hence has to be ruled out by
an ultrasound of abdomen. Certain medications like antidepressants cause weight gain.
If all these causes are ruled out then you can start a diet and exercise program to lose weight. If you want to lose weight, then you must do it the scientific way for long term benefits, healthy glow, and a good physique and body.