Yes it is possible to lose fat and gain muscle simultaneously. Weight loss will occur before you gain a lot of muscle mass. First, try and estimate how many calories you are eating now at your present weight and activity.
In order to lose weight we all know that we need to burn more calories than we expend.Â There are 3500 calories in one pound. So if you want to lose one pound a week you would eat 500 less calories a day than you are presently consuming
Generally, on the first week on a diet you will lose a few calories as the body sheds excess water. Now that you are working out you will also be burning more calories so you may lose weight more rapidly than one pound a week.
You need to eat good foods and low fats. Good foods include whole grains, fruits, and vegetables for carbohydrates. Your protein should come from lean meat, fish, poultry, and eggs. Your fats should be mono-saturated; they come from walnuts, olives, sunflower seeds, sunflower oil, flaxseed oil, and olive oil.
You need to include some aerobic activity in your exercise program to give your body a calorie-burning boost. It could be walking, biking, swimming, or jogging. Any activity that gets your heart rate up is considered aerobic.
There are computations to figure out how many calories you should eat. Some of them are based on your basic metabolic rate (BMR) or your (BMI) body mass index. You can find these equations on the Internet or in diet books.
The basic equation though is to burn more calories than you expend to lose weight. To build body mass, once you lose the fat, you will be eating more calories then you burn. Each diet has to be the right combination of foods.