How soon does muscle show up on the scale?

I am so very confused right now.  I started running at the gym three weeks ago now, in the hopes of a)getting in better overall shape since I can barely walk three flights of stairs without dying and b) losing weight.  Three weeks later and my scale says that I've GAINED 7 pounds!!!  What?!?  I've been trying to create a 1000 calories deficit every day (i.e. if i burn 2800 calories through the gym and sedentary calories, then I try to eat 1800 calories).  However, I think my deficit has been closer to 300-500 calories since I know I could be doing better on the whole "eating right" thing.  But still, I should be in a deficit every day.  Soooo, is it even possible to have gained 7 pounds of muscle in only 3 weeks?  When does the scale start reflecting gained muscle?

My current workout is usually an hour on the treadmill, alternating between walking and running (usually winds up to be half and half).  I should also mention that in order to attain my healthy weight/BMI, I need to lose 30 lbs, so this isn't like I have only 5 lbs to lose.

Any idea what's going on?

 

While I cannot offer an explanation, I can tell you that I experience the same thing when I start working out and exercising.  Bob Greene's latest book recommends not weighing oneself for the first month so as not to get depressed and "de-motivated" by any weight gain.  That has helped me to realize that some weight gain is normal when you first begin to exercise.  I am not sure, however, if the amount you have gained is normal or not.  Have you drastically increased your water intake? 

sometiems muscle swell up from all the excercising...i think its normal to gain at first....so dont weigh yourself....make sure you strectch your muscles and warm up and cool down always..this should help ease the shock your muscles are going into with all the new sudden strength training

water intake effects your weight going up??

From what I read, and from what I have experienced, the body tends to hold on to any increased water intake, at least at first.  And when exercising, the muscles absorb more water.  So this could possibly explain some of the weight gain, perhaps.

When I first started my new eating/exercising lifestyle, I lost a steady three pounds a week with good, healthy eating and daily exercise.  Now when I exercise (I tend to stop and start a lot), I always gain weight first and retain water!