Which do you think has a higher caloric value per serving, fats or carbohydrates (sugars and starch)?
1) Both fats and carbohydrates are high in calories. But one is actually better for your body than the other. Fats are definitely higher in caloric content than carbohydrates. These are stored in your body and are used up only when necessary. If you were starving, your body would rely on this store of fats for survival until a source of food could be found. The problem with fats is that once your body stores them, they are extremely hard to get rid of!Carbohydrates are used as instant fuel and are burned more readily and are therefore more beneficial to your body than fats.
2) Fiber comes from plants. Think oatmeal and shredded wheat, which come from grains (oats and wheat). Animal sources don't offer fiber.
1. When you are comparing calories per serving, you are really comparing the number of calories per unit of weight. Fats are far higher than carbohydrates in this--fats have ~9 cal. per gram, while carbohydrates (and proteins) have ~4 cal. per gram. It doesn't matter whether the carbohydrates are simple (sugar) or complex (starches), they all have the same calorie density.
2. Fiber is the indigestible part of food, and provides the bulk so that elimination happens easily. It is a carbohydrate, and is far, far more likely to be found in plant sources. Much of it comes from cellulose, which is found in plant cell walls.