Calories are important, of course. But so are other components that make up your products.
Ignore what manufacturers teach you about servings. They indicate them to create an illusion. Servings contain much fewer calories, sugars and fats than 100 grams of the same product. Read the nutritional value of the products itself and ignore the serving size.
Pay attention to the order in which ingredients are listen on food labels. The ones that make up the greatest percentage will be listed in the very beginning while those that were added in smaller quantities will be mentioned in the very end of the list. This tip is useful if you eat packaged foods that consist of several ingredients. Opt for packaged products that have the shortest list or switch to whole food.