cyclone123

Unless you're immobile, your resting metabolic rate is almost certainly above 1200. If your body burns more calories than it consumes, you will lose weight.
The tricky part is that your body can and will consume muscle tissue for energy 'as needed' -- which is what 'starvation mode' is about.
Protein is super important, but it is even more critical that you consume enough in your diet while restricting to lose weight so that you're losing fat and not muscle.
A person who is trying to maintain their weight needs approximately a half gram of protein per day per pound of body weight. But when your body is operating on a limited calorie budget, 1.5 to 2 times that is needed to ensure that your muscle mass is maintained.
And the more muscle you have, the more calories your body burns daily even without exercise, which is a beautiful thing if you ask me.