When I ask people what there goals are and why they want to start working out more often then not the reason is that they want to lose weight but I doubt this is a big shock to anyone. However this may be what the think they want but lots of people who set out to lose weight are still unhappy with there appearance after they reach there target weight and this is because there real goal and what they wanted to look at the end of there "diet"wasn't really about weight loss what they wanted was body re-composition.
What most people really want to do is change the way they look not really how heavy the are. What you need to do is both exercise and have a healthier diet. This means that through the dieting you will lose fat and through exercise you will gain muscle and muscle definition. Even if you don't lose much weight by the end of this diet you may look significantly different but going just by the scales this won't be reflected.
You have to remember that muscle weighs more than fat and this is frequently why people become disheartened when begging there new diet and exercise regime as they may lose some fat but also put on some muscle and the scales will show this as a negative but maybe the mirror will have a different story.
Also it is important not to check too much if you start a diet and measure your waist or jump on the scales every day because you won't see results straight away and this may just take away all your enthusiasm for your new diet and exercise regime. wait a week or two and you'll be more likely to see results and carry on and get to your end goals.