This is very simple and basic if you want to lose weight you need to create a caloric deficit by dropping the amount of calories you consume on a daily basis in proportion to a consistent activity level. This deficit does not have to be drastic, (remember the slight edge philosophy of small actions adding up). Obviously if your activity level drops than you have to adjust accordingly.

When adjusting your calories for fat loss it is important to not starve yourself. Don't think that if you starve yourself for 10 days and work out super intense that this will make you lose weight super fast. What you will do is invoke your body's starvation response which lowers your BMR. Refer back to my slight edge philosophy that entertains the idea of small actions adding up over time.

So basic calorie math says that 3500 calories are equal to 1 pound of body fat. If you create a caloric deficit of 3500 calories in a week combined with proper exercise and diet you will lose one pound of body fat. 7000 calories in a week will result in 2 pounds of body fat lost. This is a simple formula and it may vary depending upon your body's initial response to its caloric deficit. This is a great starting point to see how your body reacts.

Now for your body composition it is important to understand that if you are over weight your maintenance level is where your body will stay at its current condition. So in order to see weight loss you have to drop your level down. It is very important that you do not severely cut your calories because this will in turn slow your metabolism and you will lose muscle tissue. You do not need to lose muscle tissue. A good rule of thumb for you would be to cut calories in increments of 500. Never more than 1000. This will enable you to find that threshold point where cutting too much will have a negative effect. This is very important that you understand this.