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What Do Food Labels Say? – Explanation of Energy and Nutrient Data

Feeling puzzled at the grocery store or when shopping online because you're unsure how to interpret the numbers on the packaging? Do you hesitate to buy a product because you're worried it might be too high in fat? Are you lost in the maze of calories? Don't worry, we I've got you covered! Scroll down, and let us guide you through the world of energy and nutrients!

a smiling woman is looking at food product labels in a supermarket

Your body needs energy to function, which is why you eat (and because food tastes good, of course). However, it's essential to be mindful of how much energy and nutrients you're consuming and in what proportions. Fortunately, there's a wealth of information available today to help you understand what's what in this regard. On the labels of packaged products (including semi-finished or finished foods and beverages), you'll always find (or at least you should) a small table showing how much energy (kcal/kJ per unit of measure), protein, carbohydrates, and fat are contained in 100 grams or 100 milliliters of the product, as well as in one serving. Within the fat content, you'll also find the proportion of saturated fatty acids, the amount of added sugar in carbohydrates, the fiber content of the product, and the sodium content, which can also be an important factor.

In the case of sodium, the manufacturer may emphasize if it comes from natural sources in the product. This means, it's derived from the sodium content of the raw materials used and not from the salt (which is nothing more than sodium chloride) used for flavoring and preservation.

Let's Review a Bit!

You might have learned this in biology class, but a little refresher never hurts. We often talk about how many "calories" we've consumed, drank, or burned. In this case, "calorie" is a simplified term that actually refers to the unit of energy. In everyday practice, the kilocalorie (kcal) is more commonly used, but officially, the kilojoule (kJ) is also used. However, we don't usually express daily energy needs in kJ because it's harder to calculate mentally. The conversion between the two is 1 kcal = 4.18 kJ.

Roughly speaking, 1 gram of protein and carbohydrates provides 4 grams of energy to the body, while for fat, it's a little more than double, rounding up to 9 kcal per gram. Knowing these numbers is important so you can to understand that different nutrients provide different amounts of energy. It's important to have a rough idea of how much energy you need and how much you consume with a meal so you're not surprised if, for example, your clothes suddenly feel tighter or looser.

However, it's not worth agonizing over whether carbohydrates or fats are more fattening because it's not just about how much you weigh or how much you eat and drink; other factors in your diet, including the types of carbohydrates and fats you consume, matter, it is worth revisiting my thoughts on carbohydrates and fibers here. Alongside these, factors like sleep duration, the composition of bacteria in your gut, physical activity, hormonal status, and many other factors also influence what the scale shows. And even the scale isn't all-powerful because you could also look at changes in body composition (the ratio of bone, water, muscle, and fat). But let's not get ahead of ourselves!

a blue calculator next to a chocolate doughnut, pink background

Who Determines How Many "Calories" Are in a Given Product?

The calculations of energy and nutrient content are based on the values of food composition databases containing data from food chemical analyses (averages of several real measurements), and it's important to note that there may be differences between the data in different databases. Why? Because, for example, different types of apples may have been measured, and factors such as soil composition, sunlight, variety, and many other factors can affect the results. However, data from validated, i.e., checked and credible sources, is sufficiently reliable, especially for products available on the retail shelves. Of course, it matters which table you use if you want to calculate how much you've eaten or drunk.

In Hungary, there are three main options available. You can refer to the thick, paper-based New Food Composition Table, which also can be used for selfe-defence because of it’s weight. It's relatively new, having been published in 2005. Its update is in progress, and it will be available digitally as well, but that's a bit further down the line. Until then, if you're a dietitian (which I assume is a small portion of the readership), you can get acquainted with the NutriComp software even during your college studies. This software isn't intended for the general public but assists dietitians in individual or group dietary planning and the evaluation of dietary diaries. Its database is strictly controlled and closed, so users can't change it, only the software owner and developer can. This ensures that the data cannot be "messed up." You'll soon see why this is important.

The other option, validated by the Hungarian Dietetic Association, is available as a mobile application, ALSAD. Its advantage is that it can connect dietitians with clients, allowing for even closer collaboration. You don't need to manage your dietary diary in Excel or on paper, sending it back and forth. This app can help you plan what you'll eat, track your exercise habits, and monitor your laboratory parameters (e.g., blood sugar levels).

someone is holding a phone checking how many calories are in the fruits in front of her/him, with the help of an application.valaki egy telefont tart a kezében és egy applikáció segítségével nézi meg, hogy az előtte lévő gyümölcsökben mennyi kalória van (ananász, szőlő, citrom, banán, avokádó, gránátalma)

It's advisable to be cautious with other free, online "calorie calculators" because they may contain database errors, especially if users can upload data themselves. Just think about it! It matters whether someone mistakenly enters 50 kcal instead of 500 per 100 grams for your favorite chocolate. Or, in the case of a foreign calculator or app, there may be a problem with not including Hungarian foods, making it difficult to enter your grandma's bejgli or your favorite layered potatoes. Worse, the app might allow you to set a very low energy requirement as a goal, which could lead to an eating disorder.

How Do You Interpret Nutrition Information on Product Labels After This?

In general, an average adult woman, who is of average build and physical activity, uses around 2000 kcal per day, while a man uses around 2500 kcal, meaning this is what they need to provide with their diet to maintain their body weight and nutritional status (i.e., not gain or lose weight). It matters where this energy comes from. Sticking with the chocolate example, four bars of chocolate would cover the 2000 kcal, but this would be incomplete and one-sided nutrition. Even if it might seem appealing to some for a short time. The essence is a varied, balanced diet that includes all nutrients. A single serving of food doesn't tell you everything about whether you're eating well. So, it's entirely normal for one meal to contain a bit more fat, carbohydrates, or protein.

Don't Just Focus on the Numbers!

For example, a granola with nuts or seeds will definitely contain more fat than a plain muesli with just cereal grains, yet you wouldn't say one is better or worse than the other. Frequency and portion size matter, so there's room for many things in a health-conscious diet, even for that much-talked-about chocolate.

Vegetables (eggplant, corn, bell pepper, mushroom, potato, tomato, carrot) written with chalk next to the vegetables arranged on the board, indicating the calorie content of each

If you're, for example, diabetic or insulin-sensitive, it's necessary to thoroughly discuss with a dietitian how much of what you should eat and drink, and also to pay more attention to quantities. Don't worry, you don't have to constantly count and measure. Over time, you'll get the hang of it, and even without tables or apps, or with less frequent use of them, you'll feel when it's enough.

If you only take away one sentence, it should be this one: the goal isn't obsessive calorie and nutrient counting but conscious and enjoyable eating.


ScJudit Schmidt dietitian, health educator, workplace well-being program manager. Engaged in prevention, education, and background work related to health, well-being, and nutrition. Provides assistance in conveying knowledge on nutrition, health, and well-being through article writing, blogging, editing, proofreading, and creating professional texts on these topics. Also conducts informative presentations for companies and schools. Her main focus is on disease prevention and creating a balanced and sustainable diet. Her motto: the sunny side of food. Dietitian Judit Schmidt presents her profession and works in a personal, occasionally humorous style on various social media platforms under the name Youteefool.


You can find Judit on her website:

On Facebook: Youteefool

And on Instagram: Youteefool


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