How to read food labels for weight loss?

In this brief guide, we will answer the query “How to read food labels for weight loss?” We will cover relevant information such as how to calculate total calories and macronutrients from the food label, and how to use the ingredients list for an informed-decision. 

How to read food labels for weight loss?

If you want to lose weight, but you often eat packaged foods, you should read the nutrition facts at the back of the package. Nutrition facts offer information about energy, and all nutrients contained in the product; however, you should know a few things to properly read it (1,2).

All claims are based on a 2000 calorie diet; so, when you read that certain food provides only 5 % of daily sugar intake, and you are eating fewer than 2000 calories, it is probable that you are having more than 5 % of your (personalized) intake (1,2).

Prefer “low” versions instead of “reduced” versions of foods; reduced-fat and reduced-sugar claims only require a reduction between 25 and 30 % compared to the original product (3,4). 

On the other hand, low-sugar foods must provide no more than 5 g per 100 g, and low-fat products must provide less than 6 g per 100 g of food (3,4).

Moreover, must labels inform nutritional information based on a single serving, which could be from a few grams to 100 g. So, you should look for the total servings per container to know how many calories and macronutrients you are eating (1,2).

In the following subheadings, you will learn what a serving size is and how you can calculate the macronutrients and calories in a food product.

What is serving size, and how does it affect my calorie intake?

A serving size is a measurement of a certain amount of food, it can be expressed in grams (g), pieces, cups, ounces (oz), milliliter (ml), among others. This can impact your calorie intake if you do not consider the whole content in the product (1,2).

When you look at the nutrition fact label, this is calculated on a single serving size; if you eat the whole product, but you are not considering all servings in your calorie count, you may increase your total daily calorie intake (1,2).

To calculate the full calorie and macronutrients in a product, you should look for the following information (in the nutrition fact label):

  • Size of serving
  • Total number of servings
  • If the label does not provide the total number of servings you can calculate it with this procedure: find the total weight of the product and divide it by the serving size.
  • Once you have the total number of servings, just multiply every nutrient (calories, carbohydrates, fats, proteins, fiber) times the total number of servings.

How to understand ingredient lists?

The ingredients list is at the back of the package, and it reports all ingredients used in the product. The ingredients are ordered by the quantity used, starting with the most abundant and finishing the list with the less abundant ingredient (1,2).

You can use this list to detect undesired or desired ingredients.

What ingredients should you prefer for weight loss?

When looking at the ingredients list, you should identify ingredients which are linked to a better weight management (5,6):

  • Prebiotic and fiber like inulin, pectin, carboxycellulose, and resistant starches are good for weight management because they do not provide energy, feed your microbiota, and help to increase the satiety sensations.
  • Carotenoids are natural pigments, they are not that common in processed foods because they could be expensive. But carotenoids have antioxidant and anti-inflammatory properties that have been associated with a reduction of obesity risk.
  • B vitamins are normally added to food products, these are important because they can improve the metabolic efficiency, especially for nutrients’ absorption and macronutrients’ metabolism.

What ingredients should you avoid for weight loss?

There are other ingredients that are not very recommended for a healthy diet, and also in a weight loss diet. The main ingredients are the high fructose corn syrup and partially hydrogenated oils (7,8).

High fructose corn syrup is a sweetener obtained from the breakdown of corn starch and its further conversion to fructose; this sweetener is very cheap, and it has a higher sweetening capacity than sugar (7).

Unfortunately, high fructose corn syrup is linked to metabolic inflammation and irregularities in cholesterol levels. The relationship between high fructose corn syrup and obesity is still unclear, but it is indirectly associated with being overweight (7).

On the other hand, partially hydrogenated oils (or fats) are associated with a higher body weight gain and increase of adipose tissue. So, it is better to avoid these fats in your diet (8).


In this brief guide, we answered the query “How to read food labels for weight loss?” We covered relevant information such as how to calculate total calories and macronutrients from the food label, and how to use the ingredients list for an informed-decision. 


  1. Temple NJ. Front-of-package food labels: A narrative review. Appetite, 2020;144(104485):104485.
  1. Temple NJ, Fraser J. Food labels: a critical assessment. Nutrition, 2014;30(3):257–60.
  1. Mistry VV. Low fat cheese technology. Int Dairy J, 2001;11(4–7):413–22.
  1. Vanderlee L, White CM, Bordes I, Hobin EP, Hammond D. The efficacy of sugar labeling formats: Implications for labeling policy: Efficacy of Sugar Labeling Formats. Obesity, 2015;23(12):2406–13.
  1. Snauwaert E, Paglialonga F, Vande Walle J, Wan M, Desloovere A, Polderman N, et al. The benefits of dietary fiber: the gastrointestinal tract and beyond. Pediatr Nephrol, 2022.
  1. Godswill AG, Somtochukwu IV, Ikechukwu AO, Kate EC. Health benefits of micronutrients (vitamins and minerals) and their associated deficiency diseases: A systematic review. International Journal of Food Sciences, 2020;3(1):1–32.
  1. Li X, Luan Y, Li Y, Ye S, Wang G, Cai X, Liang Y, Kord Varkaneh H, Luan Y. The effect of high-fructose corn syrup vs. sucrose on anthropometric and metabolic parameters: A systematic review and meta-analysis. Front Nutr, 2022;27;9:1013310.
  1. Pai SA, Munshi RP, Juvekar AR. Partially hydrogenated vegetable oil containing 5% trans fats when combined with fructose exacerbates obesity and non-alcoholic fatty liver disease in rats. Nutrire, 2020;45(1).