Gaining while losing

Was told by a trainer that it was basically impossible to gain real muscle and lose fat at the same time. I don’t feel like this is true. I’m 18 and muscular but have not finished growing into by body yet and seem to have some fat that doesn’t want to leave, ( Especially a really thin layer over my stomach), I work out 5 to 6 days a week and eat healthy.( Only whole real foods, lean meat, good carbs, veggies, fruits, and water. Training/Diet tips to gain more muscle but still lose that little bit of extra fat?

While it is not easy to gain muscle and lose fat all at the same time, I believe at YOUR age it CAN be done! They key is going to be your diet and using cardio. You should be weight training intensely about 4-5 days per week, and also hitting 3-4 sessions of cardio after workouts or upon awakening. The foods you eat sound terrific, but you want to keep the amounts of carbs you eat under control. You want to consume just enough to fuel workouts and replenish glycogen, but not so many that they can be stored as fat. Shoot for no more than one gram per lb of body weight of carbs per day, with the majority of those carbs eaten at meal one and the post workout meal.