What Causes Weight Gain While On Clonazepam?

i have been on clonazepam for less than a year and have gained at least 10 lbs around the middle

i am a 62 year old female

non smoker/social drinker and until i tore a muscle in my leg in may doing zunba i am active

i can not fit into any of my clothes around the middle

i am in menap. since age 53 and do not take any other meds

thanks

oneida wells