Weighing is yet another topic where the experts disagree. There are pros and cons of regularly weighing yourself. Your weight can fluctuate up to 3 or 4 pounds over the course of the day, so when you weigh yourself, it is best to do so at the same time each day, with the same amount of clothing, and preferably on the same scale. I prefer weighing myself in the mornings before getting in the shower.
The Pros: One of the advantages to daily monitoring is that it keeps the weight from creeping up on you. Those who do weigh themselves regularly are less likely to have a jaw dropping experience of seeing they have gained 10 pounds since they last checked. It is easier to improve something you monitor and are aware of than something you are clueless about. It can be difficult to fine tune a weight loss program if you are not getting any feedback as to the progress you are making. It's also important to keep in mind that you are looking for trends and moving averages. There are many software applications that help you track and graph your weight to recognize these trends. Weighing can also serve as a daily reminder and motivator to eat right.
The Cons: The disadvantage to regular weighing is that it can make people stressed out, discouraged, or even neurotic. Some people want to give up if they don't see immediate weight changes, but the body doesn't always respond immediately to our behavior. I've had some clients who worked out hard and ate right, and the scale went up. I've been shocked when others confessed a week of gluttonous eating, yet they maintained their weight or it even went down! There are many variables that affect our weight besides our diet. I do not recommend regular weighing for teenage girls who are already at a healthy body weight. I would hate to be a contributor to someone obsessing about their weight and developing an eating disorder.
Your weight is just one of many feedback factors you can use to indicate how you are doing. Although I think weekly weighing is important, there are some people in excellent shape and in good health who have not stepped on a scale in years and could care less how much they weigh. They are most likely the exception.
I think a more important area to focus on is body composition as opposed to how much you weigh. If you lose ten pounds and it's mostly muscle, then that's not a good thing. It is possible to transform your physique by losing fat and gaining muscle yet weigh the same as when you started. Other useful feedback mechanisms besides the scale are how you look, feel, and how your clothes fit you. One of the best compliments you can get is when people ask you if you have lost weight. That type of positive feedback is more rewarding than just reaching a number on the scale.
So should you weigh yourself regularly or not? I do, but I think it depends on the person. The feedback is valuable, but it is not for everyone. It is crucial for some people but some personalities do better focusing on other factors as long as they don't kid themselves and deny the obvious. I recommend doing what works best for you.