However, it has to be said that I have some say in what those numbers look like, depending on when I take my measurements.
I've stopped taking official weight and measurements on Sunday mornings, because that is just too depressing.
Oftentimes, I weigh more on a Sunday than I will on the following Tuesday, because the effects of the debauchery I've engaged in on Friday and Saturday take a day or two to disappear. This weekend - for example - I went out for dinner on both Friday and Saturday nights, alcohol included. I totally overdid it on Friday, including my first REAL cheat since January, in the form of the full-sized Reese's Nightmare sundae at my local ice cream parlor. Talk about a carb nightmare for yours truly!
Also, it has to be pointed out that my weight fluctuates daily (and if you are a woman, there's a good chance that yours does as well), and throughout a given day, as well. Most of this has to do with water weight gain and loss, which can be significant.
I am a little addicted to daily weighing, which is not advisable (too easy to be discouraged). Don't follow my bad example in this regard. ((Note: for some people, especially those prone to regular swelling and those with cardiac issues, daily weighing can be critical to knowing when you've packed on too much water. We learned this the hard way with my dad and his several bouts with congestive heart failure. I'm not a doctor, and in no way qualified to give medical advice, so talk to your doctor about this issue!!))
The best thing to do is pick the same day, each week, to do your weigh in and measurements. Weigh and measure yourself in the morning, naked, after you've used the loo and before you've had anything to eat or drink (including meds, vitamins and the water you guzzle them with), preferably when your hair is dry! If you have your period, feel free to skip weigh in that week, as that can be horrifying.
Just - whatever you do - don't forget to measure yourself regularly. It can be the only thing that keeps you sane when your weight has plateaued. Frankly, I think that measurements are more important than weighing, as a general rule. Back in the Spring of this year, I was stuck at the same weight - up one pound, then down one pound - for weeks!! At the time, I was hitting the gym a lot. Measurements showed me that even though my weight wasn't changing, I was still getting slimmer and healthier as my size decreased.