People are usually looking to achieve fat reduction, not a muscle reduction.
You could be 120 pounds and look completely out of shape while someone who is 150 pounds and has significantly lower body fat will have a much leaner physique and a healthier body composition.
Optimal combination of three key factors each dependent on the other to lose fat and gain lean muscle mass will contribute to your search for perfect body:
1. Nutrition – regulate the energy that goes to your body
2. Cardiovascular Exercise – increase the amount of energy burned
3. Resistance Training – build active muscle mass and develop muscular endurance
Imagine you are on a healthy balanced diet of wholesome foods and the energy you consume is 2000 calories a day. Since you do not exercise, I will assume that your body’s metabolic rate , the rate at which your body expends the energy at rest or sleep, is 1500 calories. That means that you accumulate 500 calories every day minus your daily activity.
Now, let’s add the resistance training. When you build some muscle mass, it will increase your body’s potential energy use to, let say 1700 calories (1 pound of muscle needs about 50 calories/day just to maintain it) + you burn another 200 calories while you work out. Already you decreased the energy you accumulate from 500 calories per day to 100 calories.
Finally, lets add the cardiovascular exercise assuming an expenditure of 300 calories on treadmill or any other cardio exercise. You are now loosing 200 calories every day.