<human>: Could you distill the essence of the text into 1-3 sentences?

I made a serious change to my diet two weeks ago today - I cut out all processed sugar and am eating as few carbs as I can in general, while focusing on eating more protein. 

I've been using MyFitnessPal to count calories, and it told me I should be eating about 1900 calories a day to lose two pounds a week. I thought to myself, "Man, that seems too high", and have actually been eating between 1200 and 1500 a day. 

I stepped on the scale this morning to find that I'd lost 9 pounds (yes, NINE) in the past week. Adding that to an eight-pound loss the previous week (which I attributed to being water weight) and I'm a little worried that I'm overdoing it. Should I be sticking closer to MFP's recommendations? I'm a 22-year-old guy who started at 274 lbs two weeks ago. Was at 266 last Saturday and weighed in at 257 an hour ago. 

I'm not ridiculously active - I've been riding an exercise bike a couple of times per week and occasionally going for walks. My mother, who minored in health education in college, gave me a stern talking-to this morning when I told her how much I'd lost.

From all my number-crunching, I'm fairly sure I've been getting all my necessary nutrients (I also started taking vitamins again as part of my new routine), so I guess my question is this: is there anything inherently bad about losing too much weight in a short period of time?
<bot>: 6'3"/M/22, went from 274 lbs to 257 lbs in two weeks; am I overdoing it?