What Should You Check First When Evaluating a Nutrition Label?

November 16, 2025 •

4 min read

According to the FDA, many people do not consume enough dietary fiber, Vitamin D, calcium, iron, and potassium. However, before diving into these details, you need to know what to check first when evaluating a nutrition label to understand all the information correctly.

Quick Summary

The first step in analyzing a nutrition label is to check the serving size and servings per container. This initial check is crucial because all other nutrient values are based on this information.

Key Points

Start with Serving Size: All other label information is based on the serving size, so check it first to avoid miscalculations.
Check Servings per Container: This tells you how many servings are in the entire package, which is crucial if you plan to eat more than a single serving.
Pay Attention to Added Sugars: The updated label separates added sugars from total sugars, making it easier to limit empty calories.
Limit Saturated & Trans Fats: These unhealthy fats can raise cholesterol; aim for low saturated fat and zero trans fat.
Compare Sodium Levels: Processed foods can be high in sodium, which is linked to high blood pressure; compare products using the %DV.
Look for Beneficial Nutrients: Seek out products with higher percentages of fiber, Vitamin D, calcium, iron, and potassium.
Use Percent Daily Value (%DV): This percentage gives a quick snapshot of a nutrient's contribution to a daily diet, with 5% or less being low and 20% or more being high.

Why Serving Size is Your First Priority

Every piece of information on a nutrition label, from calories to sugar, is directly tied to the serving size listed at the top. Forgetting to check this critical detail can lead to vastly inaccurate calculations about what you are consuming. For example, if a package contains two servings but you eat the entire package, you have consumed double the calories, fat, and other nutrients listed.

The serving size on a label is standardized by regulators to make comparing similar foods easier, but it does not represent a recommended portion. It is simply a reference point. Understanding this distinction is the key to accurately interpreting the rest of the nutritional data.

The Impact of Multiple Servings

Consider a snack bag with a stated serving size of 1/2 cup, but the entire bag contains two servings. If you finish the bag while watching a movie, you are not consuming a single serving's worth of nutrients. You are consuming twice that amount. This simple, yet often overlooked, fact can dramatically impact your daily intake goals for calories, sodium, and fat.

Comparing Products Effectively

When comparing two different products, checking the serving size is the only way to ensure a fair comparison. If Brand A's cereal lists 10g of sugar per 1 cup serving, but Brand B lists 8g per 3/4 cup serving, a direct comparison is misleading. You must adjust one to match the other, or better yet, use the 'per 100g' column some labels provide to standardize the data.

After Serving Size: Key Nutrients to Examine

Once you have a handle on the serving size, you can move on to the next tier of information. Your specific health goals will dictate which nutrients to focus on, but generally, you want to limit nutrients associated with negative health outcomes while maximizing beneficial ones.

Nutrients to Limit

Added Sugars: The new nutrition labels list "Added Sugars" separately from total sugars. This distinction is vital because added sugars contribute calories without providing many nutrients and are linked to weight gain and heart disease. Check this line and aim for products with low or no added sugar.
Saturated Fat & Trans Fat: Found under the 'Total Fat' heading, saturated fat and trans fat can increase LDL ('bad') cholesterol. Aim for products with low saturated fat and, ideally, 0 grams of trans fat. The ingredients list may contain 'partially hydrogenated oil' even if the trans fat is listed as 0g, meaning it contains trace amounts.
Sodium: A high-sodium diet can lead to high blood pressure and heart disease. Compare products and aim for those with a lower % Daily Value (%DV) for sodium. Processed and pre-packaged foods are often very high in sodium.

Nutrients to Get More Of

Dietary Fiber: Fiber aids digestion, helps you feel full, and can lower cholesterol. Look for products with higher fiber content. Good sources of fiber are often labeled as such.
Protein: Essential for building and repairing body tissues, protein also promotes satiety. Check the label to see how much protein is in each serving, especially if you are focusing on muscle gain or weight management.
Vitamins and Minerals: The label lists key vitamins and minerals like Vitamin D, calcium, iron, and potassium. Look for products with a higher %DV for these to help meet your daily requirements.

Comparing Product Nutrition Labels

Using the knowledge of serving size and nutrient priority, you can effectively compare products. Let's look at two hypothetical breakfast cereal options.


Nutrient (per serving)	Cereal A (1 cup serving)	Cereal B (3/4 cup serving)	What to Look For
Serving Size	1 cup	3/4 cup	Standardize to compare fairly. Cereal B's label values would be multiplied by ~1.33 for a direct comparison per cup.
Calories	250 kcal	180 kcal	When standardized, Cereal B is actually ~240 kcal per cup, making them similar.
Added Sugars	12g (24% DV)	6g (12% DV)	Cereal B is significantly lower in added sugar and a healthier choice.
Dietary Fiber	3g (11% DV)	4g (14% DV)	Cereal B offers more fiber per standardized serving, which is a positive attribute.
Sodium	180mg (8% DV)	120mg (5% DV)	Both are relatively low, but Cereal B is slightly lower in sodium.

From this table, Cereal B, despite its smaller serving size, is the better nutritional choice when you account for the difference in serving size. It provides more fiber and less added sugar and sodium, making it the healthier option for a balanced diet.

Conclusion: A Quick Guide to Informed Decisions

Reading nutrition labels does not have to be a confusing task. By first checking the serving size and comparing it to your intended portion, you establish a correct foundation for all other calculations. From there, prioritize checking for added sugars, saturated/trans fats, and sodium, aiming for lower numbers. Finally, look for beneficial nutrients like fiber, protein, and essential vitamins and minerals, aiming for higher percentages. Armed with this simple, step-by-step approach, you can confidently navigate the grocery store aisles and make smarter choices that align with your health and wellness goals. Always remember that the serving size is the key that unlocks the rest of the label's information. For further official guidance, the FDA's guide on reading nutrition labels is a reliable resource.

Frequently Asked Questions

Serving size is the most important factor because all other nutritional information, including calories, fat, and sugar, is based on that specific amount. If you eat more or less than the stated serving, you must adjust all other values accordingly.

Total Sugars includes both natural sugars (like those found in fruit and milk) and sugars added during processing. Added Sugars are listed separately to help consumers identify how much sugar was put into the product and is not naturally occurring.

The % Daily Value (%DV) shows how much one serving of a food contributes to a 2,000-calorie daily diet. To compare products, aim for a lower %DV for nutrients like saturated fat, sodium, and added sugars, and a higher %DV for beneficial nutrients like fiber, vitamins, and minerals.

A %DV of 5% or less per serving is considered a low source of that nutrient. A %DV of 20% or more per serving is considered a high source. Use this rule of thumb to choose foods that are low in nutrients you want to limit and high in those you want more of.

Yes. Even if a label states '0g Trans Fat,' it is legally permitted to do so if the amount is less than 0.5g per serving. 'Partially hydrogenated oil' is a sign that the food contains trans fat, and it is best to avoid it, especially if you consume more than one serving.

Focus on finding products with higher amounts (and a higher %DV) of dietary fiber, protein, Vitamin D, calcium, iron, and potassium, as these are beneficial for overall health.

To make a fair comparison, you need to standardize the serving size. You can either use the 'per 100g' column if available, or manually calculate and adjust all nutrient values to match a consistent serving size.

Not necessarily. When fat is removed from a product, manufacturers often add sugar or sodium to improve the taste. It is important to check the rest of the nutrition label for these ingredients before concluding a product is healthier.