You know already if we eat more calories than our body can burn we gain weight. It's true that certain foods will boost your metabolism but only if you eat them as a part of a effective diet and weight loss programme. Fat burning foods. Fat burning food #1: Apples: Do you remember the old saying "An apple a day keeps the doctor away". Well not only a doctor but also the extra pounds as well. Apples contain the highest percentage of pectin, this is a soluble fiber. There was an interesting study in Brazil about weight loss and apples . 2 groups of dieters were getting exactly the same amount of calories but with one exception. One group was getting an apple before each meal. And this group lost 33% more in weight.