This is just something I read, and felt it is an interesting piece of information for those on a diet, actually for almost everyone. When on a weight-loss program, we tend to measure our body weight. However, that is not the best indicator. Our body weight is a combination of both fat and muscles. Now, muscles are good because they help in burning more calories. So, it's better to reduce body fat instead of simple body weight. There are techniques like underwater weighing, and electrical impedance to measure body fat. But all these have a certain degree of inaccuracy. So make sure you understand exactly how the measurement is being done. However, I still rely on the good-old weighing scale for a weekly status on how I am progressing. It is much simper!
Yes, I completely agree with Swati regarding relying on body fat measurement instead of body weight. I am a certified fitness trainer and I get disappointed looks after some of my clients weigh themselves and find out they've only lost a few pounds even after a whole week of regular moderate to high intensity exercise and proper food intake. I always explain to them that because they lift weights, there is a huge possibility that their fats have been replaced with muscles therefore although their bodyweight is still almost static after all their hardwork, it's more muscle weight now than fat weight. I encourage them to allow me to test their %body fat using the good old reliable caliper. And I usually get bigger smiles and sighs of relief and much more satisfied clients :-)