How to break the plateau?

The firs questions you'll get is do you weigh your food and can you make your diary public.

You can work out for 8 hours a day, 7 days a week. But if you aren't in a calorie deficit you won't be losing any weight or you could even gain.
Losing weight is 80-90% calories/food and 10% exercise. Having said that, you can lose weight with zero exercise.

Long story short, if you were truly only eating 900-1000 calories, the weight would be falling off of you. Barring any medical conditions ofcourse

Check out this article...it's something I'm currently paranoid about myself. A 900-1200 net calories can have negative effects.

http://www.metaboliceffect.com/starvation-mode/

Try mixing up your calorie intake. The body is always trying to achieve homeostasis, so if you are in a long term caloric deficit, your body will change in order to meet it's new caloric intake.

For example, to maintain my body weight I need about 3200 calories a day. 2700 calories a day will lead to 1 pound lost a week. It's not that simple though. If I eat 2700 calories a week, for a long period of time, my body will adapt by shedding muscle mass and slowing my metabolism until it can be supported by my new calorie intake. I can tell when this is happening because I lose strength and am tired all the time.

A better approach is to vary day to day, or even week to week calorie intake. Maybe instead of eating 2700 calories a day I will eat 2700 calories one day of the week, 3000 calories a day 3 days, and 2400 calories a day the other three days. You can also have days or weeks where you intentionally go above your maintenance goals. Maybe I would have a couple days where I eat 3500 or even 4000 calories, and I have some weeks where I have a net calorie surplus and gain weight.

If you are in a constant calorie deficit, your body thinks it is starving and will change to fix the problem. You have to vary your diet in order to keep it from adapting.

I'm by no means an expert on this but have a lot of personal experience and have done quite a bit of research. Hope this helps.

You are NOT in a plateau.

Water weight is a temporary weight gain that can mask your results - and its typical to retain water when you start a new workout routine or increase workout intensity. Its because your muscles need extra water for repair. Other common causes for water weight are high sodium intake, sleep disruption, stress.

Do fuel your body. You want to lose weight, but do you want to cause damage along the way? And trust the process. You are confident that putting gas in your car and doing regular maintenance is necessary to keep your vehicle on the road for the long term, right? Food is the same, as a source of fuel for the body.

Google your BMR, its the amount of calories your body (based on height/weight/age/gender) uses in a day to handle basic functions. Then you burn more calories as you use energy to move thru your daily activities, and for cardio where you're moving multiple muscle groups for an extended period of time. This will help you to better understand how you can create a deficit for weight loss and still eat 1500-1800 MINIMUM. From there, just give it time.