How much progress have you seen in these two months? Where did you start (weight and/or "before" pic)?
It might be "sufficient" if you've been seeing steady results each week, but 1200 calories is really low for a 140-pound guy who trains hard several days per week. The breakdown of those calories (like if you're doing low-or-no carbs) is also a factor.
What does your training look like? Days, exercises, sets, reps, cardio.
These articles talk a bit about why you don't want to go too low calorie:
A couple weeks, maybe a few weeks, probably just a little while. Really, that's a vague question that's tough to answer, especially without details of where you're coming from/what you've done so far.
If you were 160 two months ago or if you were 145 two months ago, that's a big of a difference. Or if you're doing currently lifting four days a week and doing an hour on the treadmill everyday vs lifting three days a week and the only cardio is walking 10 minutes to and from the gym.