I eat a healthy diet and go to the gym 5 days a week, burning about 300 cals each time. i'm 9st 4, is this enough exercise to loose weight?8st my goal

Math problem: Assuming you were in a relative steady state prior to your exercise program.....To loose 1 stone or 14 pounds you need to have a negative caloric intake of approximately 46, 200 calories. At 300 calories per day you would reach your goal in 154 days. As you can see, exercise must be coupled with a diet program to work best. "healthy" diet does not always equal low calorie diet.