I assume from your question that you are asking about losing weight, or reducing body size overall. The reality is that there is only way way to do this, and that is to change your energy balance. Everything you eat has calories in it, which are a measure of the energy that the food can provide for your body. Everything that you do burns calories. If you burn more calories than you burn, then you will lose weight.
The best way to lose weight is to use a combination of reducing how many calories you eat, while increasing how many calories you burn. You burn calories through exercise. Exercise will help you build muscle, which will make you look leaner. Muscles also burn calories even when they are resting, so as you increase your muscle tone, you will improve your energy balance. You can also reduce the amount of food you are eating to further improve energy balance. However, you should speak to your doctor or other health professional before you start on such a program, just to make sure it is safe for you to do so.
I agree with pacorz. After consulting your physician you can give 'On the spot jogging' a try. It's a very simple and good cardiovascular activity and might help you lose weight quit quickly. However, you should have a good warm up before.
you can either eat little every meal you have or if you eat several times a day, consume little amount every time.
try to excercise early morning with empty stomach so that your body uses fats to sweat rather build muscle with the food you'd taken before.
thats actually all i can say,
hope it helps!