As a trainer, I am often asked for advice on dieting. Usually people are focused on the number of pounds they want to lose. Some of the best advice I can give is to put less emphasis and importance on some arbitrary number on the scale. This is extremely hard to do for some people because our culture places so much pressure and importance on body weight. Ultimately however, your body composition is far more important than your weight as measured in pounds. I would suggest to you that your waistline measurement is a more accurate indicator of your health and body composition than your scale weight. Humans tend to store a lot of bodyfat around the midsection, so if I know your waistline measurement, then I have a much better idea what you're made OF! So a really smart thing to do, prior to beginning a diet or an exercise program, is to write down your waistline measurement. I have trained clients who made dramatic changes in their body composition, without really seeing a dramatic corresponding reduction on the scale. But those same clients DID see a big reduction in the waistline. This is because muscle is more dense than bodyfat, and an equal volume of muscle weighs more than fat. Plus because we store most bodyfat around the middle, that's where you'll see the biggest difference in your appearance. So just take a tailor's tape, put it around you right at the bellybutton, (not necessarily the narrowest part of waist), and don't pull it tight. Measure fairly every time, or you're just tricking yourself.
So keep in mind that if you are measuring your progress only with the scale, then you could possibly be setting yourself up for some disappointment.
With that being said, if you have a significant amount of weight to lose, let's say more than 30 lbs, then certainly you can keep up with your weight loss in pounds. A reasonable, sustainable rate of weight loss (it's really better to call it FAT loss), is about 2 or 3 lbs/week. We've all seen the amounts of weight people are losing on The Biggest Loser. This show can be very misleading. We routinely see people losing more than 10 lbs/week. You must understand that one pound of bodyfat is equal to 3500 kcal of stored energy. A hard workout may burn 400-600 at the very most in one hour. If you do some math, you'll see how it's impossible to lose 10 lbs of FAT in one week. So if they are not losing bodyfat, then what are they losing? Mostly water! So that is why at some point a few weeks into the contest, when their hydration levels even out, we STOP seeing these huge weekly numbers, and it's why in fact some contestants even GAIN or stay the same at some point. Weight loss is not linear. You will plateau, hiccup, come up a bit, go back down, etc...as long as the general trend is down then you're doing good!
One other note on this subject is that there are different body types. Depending on how you're built, you will have a tendency to store more or less bodyfat in certain areas. As much as we see info in the media to the contrary, you can't change your body TYPE. If you're tall and thin and linear, you're not going to magically become more compact and stocky. If you're not built "long and lean", there is no exercise in the world that is going to make you become that way. You do the very best with what you've got. People who tell you otherwise are being dishonest and are trying to sell you something that you don't need and is not going to work. This is not meant to discourage you. Quite the opposite, this is meant to free you of the burden of trying to achieve something unrealistic and feeling inadequate because it doesn't happen. That doesn't mean a person can't make dramatic, even phenomenal changes in their appearance. If you're 5' 9 and weigh 290lbs, and you lose 90lbs....trust me it's going to be dramatic. But you will still have the same bones and muscles that are the same length, just minus all that bodyfat!!