There have been studies done where if you lock a person in a room (voluntarily) and control their calorie intake the participants will lose weight 100% of the time, no exceptions.

So to answer your question succinctly, it is impossible not to lose weight if your calorie intake is lower than your calorie burn rate.

With the said it doesn't mean it's easy to lose weight. Something you might need to remember that might help, food manufacturers are allowed a 20% margin on what they declare as calorie content. Many of them take advantage of this and purposely under declair on the pack so your 1 200 calories a day could legally be as high as 1,439 calories. that's not mentioning that in studies most people massively underestimate the portion sizes they're, unknowingly consuming more calories than they think.

The only way around this really is to 20% to the calorie count of everything g you eat and to measure all portions