I have read that a daily diet of less than 1000 calories is bad for the metabolism. I am in the first week of soft foods, 4 weeks from surgery. I have been tracking my food on "FitDay" and seem to average around 690/day. Is this too low? Does it really matter about calories?

I have not counted calories from day one and have had great success. If you are one that LIKES to count, measure and track, then 690 does seem low.

When you are in the maintaining stage and if you consumed this little amount of calories the whole time, you are going to have a very hard time mainting. I hit a plateu for 3 weeks, I increased my calories to 1000-1200 and excersize 3 times a week and it started dropping again. Eat like youre going to eat as a skinny person. But its recommended not to be less than 1200 from what i read.

In the beginning/healing stages it's really difficult to get in many calories... At least it was for me. My first few weeks I was lucky to get in 350. My doctor actually told me to start drink regular juice instead of sugar free because I have hypoglycemia(since being banded) just so I could get some more calories in. Obviously, I'm not recommending that unless you talk to your doctor first, just wanted to let ya know that I've been there... It's difficult in the beginning. But then before you hit restriction it will be difficult(at least is was for me) to stay between 1000-1200 some days :-)

You NEED a certain number of calories just for your organs to function including your brain, heart, lungs, etc. You can find that number out - google "Resting Metabolic Rate calculator" and plug in your height/weight, etc That is the MINIMUM number of calories you should be getting in order to just sit on a couch and breathe. If you are more active, that number can be adjusted. For instance, I am 5' 8" and weigh "X" pounds (sorry, can't share that number) so I need around 1600 calories a day. If you are concerned, I would speak to your nutritionist about it. I think 690 is really very low and so your body is going to start attacking itself and you won't have any energy at all. Good luck.