Is this a good weight loss plan?

I haven't eaten anything but 300 calories in the past 28 hours. In 6 hours, I will consume another 300 calories. The calorie consumption is through lean cuisine. I've been drinking plenty of water which makes my stomach feel full. I plan to heat the water and drink it so that I'll have something warm in my stomach. If I continue on this path, how much weight will I lose in a week? I'm taking a thyroid pill to increase my metabolism as perscribed by a physician. I want to weigh 165 pounds. I weigh 275 now and am 5 foot 9 and a half. How much can I lose in a week?