Why do the scales stand still when I exercise???

How many calories are you netting per day? If you're stagnating, you might want to add 100-200 calories a day, because your body might be holding on to weight because it thinks it's starving. I usually stagnate for a little while when I'm building up a lot of muscle, and I'll add a couple hundred calories and then drop 1-2 pounds in a week. Just keep eating good food and exercising, and the pounds will come off eventually

The scales don't reflect everything. Two examples from my own life:

I got sick and bedridden. I lost 7 pounds in a month without trying and with eating the same diet. At first I thought "Great! I lost 7 pounds!" But then I realized my measurements stayed the same and I had gotten flabby. I lost muscle tone.

Another example: The scale is staying the same, but my waist measurement is decreasing, and my arms are becoming more muscular. I am getting in shape even though the scale says the same thing.

How are your measurements doing?

Because when you first start to exercise or increase intensity, your muscles store extra glycogen in anticipation of the next workout. In order to store glycogen, water is required. This is what we refer to as "water weight". It is not the same as bloating when you consume too much sodium or something. It would be barely noticible except with the scale. It can be enough to mask small losses in fat and frightens many people off of exercise. Or people often assume they are gaining muscle. It is one of the reasons why scale weight isn't a reliable indicator of progress.

When I changed up my workout routine to lifting heavier, I gained two pounds and stayed there for an entire month. My measurements barely changed, but in the before and after photos you can see a big difference.

It is temporary and eventually your weigh loss will catch up and the scale will begin to move again

ETA - this is also the explaination for the big drop when dropping your carbs. Carbs are stored as glycogen in the muscles. When you lower carbs, the stores drop and the water weight is released. Binge on carbs and you'll suddenly increase in weight as the stores are replenished.

This!
(Thank you for not telling her she's in starvation mode.)

So? It's possible that I have lost.. I'm just gaining too? That sounded bizarre but you know what I mean!

Anyone know just how much water these muscles can hold??? Lol

Like? If I'm on a deficit that shows I've lost 2 pounds.. And it doesn't show on scale then let's assume there's two pounds of water in my muscles. So? By the time I create another 7000 calorie deficit I should see it on scales! Or am I to assume my muscles are now holding 4 pounds of water?

Somebody educate me

Yes, it is possible you have lost fat but it is not showing on the scale due to water fluctuations for any number of reasons. Since you are saying you notice it when you start to exercise, the glycogen storage is a likely issue for the initial few weeks and a couple of pounds. If we start talking about a consistent trend upwards, it may not be.

Again, part of the problem is using the scale to measure progress. The time frame is also an issue. Over a longer period of time, the scale can show us a trend, but over the short term it can easily be influenced by a number of factors that can mask a weight loss trend.
Weight loss is not linear, there are any number of factors that affect scale weight as noted in the link I posted above. It depends on how you are "creating" the 7000 calorie deficit. Yes we know a pound is about 3500 calories, but weight loss isn't quite that simple. There are a number of factors that may come into play. There is often overetimatation of calorie burns, underestimation of food intake, hormones, and other factors that can affect the weight loss. Over time, it will eventually come off if we are maintaining a deficit, but a 7000 calorie deficit does not always translate directly into a 2 lb weight loss.

Start looking at it over a period of time, not just week to week or worse, day to day, along with other things like measurements and progress photos. If you notice the scale stop moving when you start exercising, continue to exercise and monitor the scale progress along with other progress measures over a few weeks (like more than 2 or 3) and then see how it is trending, up or down.

Also , as Deksgrl noted, 2 lbs a week is far too high of a goal for someone with 15lbs to lose. It is only a reasonable goal for someone with 100lbs or more to lose.

I found this too, but it was infact that I was putting on more muscle which is heavier then fat.