Well, when wanting to lose weight you have to know the chemistry behind food and also how your body responds to what you eat. If you want to lose 1 pound you have to reduce your calories by 3500 or burn 3500 through exercise to reach that goal.
Because fat has more than double the calories than protein and carbohydrates, and doesn't aid in a sense of fullness you often eat more and get too many calories in one sitting.
Food plays one of the most important roles in weight loss. Exercise is vital, but if you are still eating more than you are burning you will not reach your goal. The more you know about food, the less of a mystery it is. Weight loss and being healthy really is attainable.