I found this to be quite interesting.
If you're trying to lose weight, in can be hard to suppress the urge to check
the scale often. It's better to exercise some restraint, though, because it's
very normal for body weight to fluctuate a few pounds from day to day - or even
within a day.
For example, if you have a large meal, you could weigh as much as 5 pounds more
immediately afterwards. If you eat food that's high in sodium, you're likelier
to gain a few pounds of water weight in the short term.
THE SOLUTION: Weigh yourself no more than once a week. You'll get a more
accurate picture of how well you're losing weight over time.