I believe that there is a few things that come into play when one increases the amount of calories you eat.
one of then is that if you increase (lets say) the amount of carbs you eat your body will hold on extra fluid to store those carbs so really when you see the scale go up. it's not fat that is being added on, it's more than likely water.
I know, either way the extra weight registering on the scale is no fun to see.
I have a feeling that if you gradually increase those calories (like already stated) by a couple hundred, you may see a tiny weight gain but it should also level off and may go back down to your goal weight/range in no time.
| Pounds lost: 4.4