Yes during menopause hormonal changes occur in body that is why due to this hormonal imbalance some women gain weight. Remedy is first you have to make balance between your hormone. Yoga will help you in this case. There are some specific yoga technique which help you to maintain your hormonal balance. Then after proper diet and exercise schedule. It is not like that you are vegetarian so your diet is healthy and you are consuming less calories. 30 min brisk walk only burn 100 kcal where if you eat 100 gm chips you consume 550kcal. So all you need proper diet and yoga counselling.