Table of Contents
Instructions for Using the Nutrition Calculator
When on a special diet, you should be careful not to exceed the kilocalories that
correspond to you per day.
Reading food labels is useful for keeping track of calories, but the trouble begins when
dealing with fresh foods or those that do not have nutritional information readily available.
To make your job easier, we offer you an online calculator for kilocalories and nutrients
of foods.
To use it, you simply have to enter two pieces of information: firstly, the
food and, secondly, the amount of it.
The tool will give you the nutrients, energy, and other characteristics about the specified
amount of the product in question.
Manual Calculation of Food Kilocalories
The traditional method for estimating the amount of kilocalories
of a food is carried out in a laboratory using a calorimeter. Based on its heat production, its
energy contribution is counted.
Currently, food manufacturers, in addition to declaring the caloric contribution of their
product, must also specify its nutrients. They do so relying on the scientific method of Willbur Olin Atwater,
who was the creator of the first caloric table of foods.
In 1890, Atwater and his team studied about 500 foods
approximately, creating a table where they declared the kilocalories, proteins, fats or lipids, and
carbohydrates of the foods, as well as water.
In a world in continuous evolution, anyone who has a phone, or a computer, with the right
application (like the calculator on this page) can easily calculate and control the kilocalories
consumed during a day.
Without the need to resort to any technology, you can also do your manual calculation of
food kilocalories.
For this calculation, it is essential to learn and keep in mind the correct way to quickly
calculate how many calories a food has, knowing only the amount of lipids (fats), proteins, and
carbohydrates it contains.
To do so, you will need to have at hand the numbers we are going to give you in this table:
Macronutrients | Energy value per gram |
Carbohydrates | 4 kcal/g |
Proteins | 4 kcal/g |
Lipids (fats) | 9 kcal/g |
Atwater Factor
The values indicated in the table are the result of a study on nutrition
carried out by Wilbur Olin Atwater, who first studied the behavior of the energy released by foods
within the organism.
The result showed how the organism was capable of absorbing 97% of carbohydrates, 95% of
lipids, and 97% of animal proteins (78% for plant proteins due to the variation of the amino acid
profile).
If you want to calculate the calories of a food, you must multiply the
numbers from the previous table by the amount of the corresponding macronutrients of the same.
Example of calculation
50 grams of chickpeas contain 31 grams of carbohydrates, 10.23 grams of proteins, and 3
grams of lipids.
Multiply the 31 grams of carbohydrates by 4 Kcal/g, the result is 124 kcal.
Now it's the turn of the 10.23 grams of proteins by 4 Kcal/g, the result is 40.92 kcal.
Finally, the 3 g of lipids by 9 kcal/g, the total is 27 kcal.
Now we just add the three results: 124 + 40.92 + 27, which gives us a total of 191.92 kcal.
The data in the table we showed you above (although accurate) represent an average value
and may undergo some variation (up to 9.5%) that are caused by one or more factors, some particular
cases would be:
The calories derived from lipids or fats are approximately 9.5 kcal/g, while those from
plant-based fats are 9.3 kcal/g.
The calories from carbohydrates (such as nuts) are 3.75 kcal/gram while those containing
carbohydrates from cereals, starches, tubers, and fruits are 4.22 kcal gram.
It's not just energy: don't forget the nutrients
Counting calories is very useful for maintaining a balance between the energy you consume
and the one you spend. If you want to lose some pounds, the quality of the foods as well as their
energy contribution is important.
It will never be the same to follow a 1500 kcal diet that contains fish, chicken, cereals,
vegetables, and fruits to one of the same amount of kilocalories in which only pastries and fried
foods are consumed.
Many of these data can be obtained with our tool: proteins (amino acids), lipids (trans,
saturated, etc.), carbohydrates (fiber, sugar, etc.), minerals, vitamins, water, cholesterol,
caffeine, alcohol, and many nutritional characteristics.
Calories or Kilocalories?
It is common to refer to the energy we consume (or that we spend) as calories
or kilocalories. Notice how the labeling of foods and
nutritional composition tables always appear expressed as kcal.
You might think that calorie and kilocalorie are the same, but that is a mistake. The truth
is that a kilocalorie is the amount of energy to raise the temperature
of 1 kilo of water by one degree Celsius. When extrapolated to the calorie,
it would be the amount of energy to raise the temperature of 1 gram of water by one degree Celsius.
In short: 1 kcal is equivalent to 1000 cal, our body weight is
expressed in kilos so it is more practical to say that a person of 55 kg requires 2000 kcal, rather
than saying that the same person requires 2,000,000 cal.
Taking that into account, foods must indicate the amount of energy they offer in terms of
kilocalories.
We hope this article has helped you solve all your doubts on the subject, if so, do
not hesitate to share it on your social networks with all your contacts, thus helping
this community to grow.
Finally, if you find errors in this calculator you can contact us so that we can solve it
as soon as possible.
Bibliographic references
University Clinic of Navarra. Medical dictionary. Kilocalories. Available at:
https://www.cun.es/diccionario-medico/terminos/kilocaloria
Biographies and life. The online biographical encyclopedia. Wilbur Olin Atwater.
https://www.biografiasyvidas.com/biografia/a/atwater.htm
Lozano, José. Nutrition is Science. University of Murcia. 2nd Edition. November 2011.
Available at: https://www.um.es/lafem/Nutricion/Contenido/Libro_completo.pdf
U.S. Department of Agriculture, Agricultural Research Service. 2018. USDA National Nutrient
Database for Standard Reference, Release. Nutrient Data Laboratory Home Page,
http://www.ars.usda.gov/nutrientdata
U.S. Department of Agriculture, Agricultural Research Service. 2018. USDA Branded Food
Products Database. Nutrient Data Laboratory Home Page, http://ndb.nal.usda.gov
Bachelor's degree in Nutrition and Dietetics from UCV. Postgraduate diploma in Public Management
in Nutrition from UBV.
Raquel Mendoza Hernández holds a degree in Nutrition and Dietetics from the Central
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