I don’t focus on weight loss, but rather in the overall physical and mental improvement. Weight can be a negative factor for many people and it can make them lose their motivation and drive. BF% is one factor I like to refer to and then look at other improvements they have made in their lives (lifestyle, mood, goal achievements, etc.). People who get fixated with their weight (no matter what the number is), they miss the big picture.
Although weight loss is a goal for many people, I try to have the client focus on all of the other wonderful benefits of an exercise program. For example, more energy, reduced stress levels, reducing risk of diseases, better mood, better sleep, etc… These benefits can be almost immediate and can help the client shift some of the focus from weight loss–where results are not as fast. Weight loss can almost be thought of as a great side effect of an exercise program and healthy diet. Also, as Michael already mentioned, body composition is also a good indicator
of healthy changes.
Hope some of these reasons help.