Starvation mode is when your body decides that you are in the midst of a famine. It doesn't know that you just aren't hungry; all it knows is that it needs to hang on to every bit of fat it can. I hate to tell you this, but you need to get at least 1200 calories per day. I had the same problem, and it caused me to stall for several weeks before I realized what was happening.

What you want are calorie- and fat-dense foods that will bring you up to at least 1200 a day. Also, I find that if I eat several small snacks throughout the day, plus dinner, I can get enough calories. I think eating throughout the day activates my metabolism as well, giving me more of an appetite.