You will absolutely need to cut out the typical foods you would normally eat that prepare you for long-distance or high-intensity training (also known as "carbo-loading"). Those will directly conflict with your weight loss goals. When cutting out those foods like rice, pasta, breads, cereals, oatmeal, etc., and eating only FASTIFIER approved foods, you might notice your athletic performance will temporarily dip while your body adjusts to burning ketones (fat) instead of glucose (sugar/carbs).
However, if you continue eating FASTIFIED foods you will notice that you will become an even better athlete! You will loose weight and body fat and eventually perform better athletically.