There are so many nutrients in food, so many ingredients, so many facts to know about what's supposedly good for you and what's supposedly not? Fortunately for all of us, the US Food and Drug Administration (US FDA) created a standardized format for the nutrition label that all processed and/or packaged consumer foods must affix to the outside of their product. So, no matter what the food, you can easily compare its value to you with that of any other food.
There are 3 fundamental areas to look for first on a nutrition label, and they're all conveniently grouped together near the top, just under the title 'Nutrition Facts'.
What is the Serving Size: standardized amount (like cups or tablespoons or pieces) followed by the equivalent amount in the metric system (such as grams). In general
How Many Servings Per Container: Most packaged foods contain multiple servings in a single package, making it easy to double, triple, quadruple, etc. the caloric intake from that of a single serving.
What are the Amount of Calories Per Serving: Typically, a single serving of around 40 calories is considered low-calorie, around 100 is considered moderate, and 400 is considered high-calorie.
Keeping tabs on the amount of servings you take in, based on the caloric intake per serving, is one great way to manage your weight. Another is to balance out eating high-calorie foods with some low-calorie foods earlier or later in the day.
The next step to using nutrition labels to help control your weight is to get the most nutrition out of the calories you take in.
Use the Percentage Daily Value to tell you how rich in each of the required nutrients the food really is. Daily values are based on a 2000-calorie diet. 5% or less of a nutrient's %DV is low, 20% or more of a nutrient's %DV is high. Limit your amount of Total Fat, Cholesterol, and Sodium. No daily requirement exists for Trans-Fats (the most dangerous kind), though their quantity per serving does appear on the label; so just be sure to keep them to an absolute minimum. Make sure to get plenty of Dietary Fiber, Vitamin A, Vitamin C, Calcium, and Iron.
Once you have gathered all the information you need, you simply ask yourself if a food choice is a wise choice for you in terms of both calories and nutrients, and whether it makes more sense for you as part of a meal or as a standalone snack. If the answers to these questions don't satisfy you for a particular food, then the next question to ask yourself is whether you can find a suitable alternative. The answer that question is almost invariably, 'Yes'.