Ditto what others have said. And, when the scale trends up on a "monthly" basis, it's not, of course, really a pound of fat we've gained--it's water retention.
In addition, when I started adding some jogging intervals, I found my weight went up drastically, and I was reading about how we build muscle--and it seems there's a stage in there that causes water retention in our muscles. When my legs stopped aching from the added jogging, the "gain" went away as quickly as it had come.
The bigger we are, the more water we can retain.
Remember, salty food--or inadequate hydration--can also cause water retention from day to day.
Hydrate, be aware of monthly fluctuations (I find weighing daily helps there), and recognize that if the scale is up 2 pounds today and down 3 the day after tomorrow, you're still headed in the right direction. And those 2 pounds gained were probably water.
Last edited by Vortex_VVV; 06-20-2014 at 12:29 PM.